US3190222A - Impact sensitive top fuze - Google Patents

Impact sensitive top fuze Download PDF

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Publication number
US3190222A
US3190222A US212517A US21251762A US3190222A US 3190222 A US3190222 A US 3190222A US 212517 A US212517 A US 212517A US 21251762 A US21251762 A US 21251762A US 3190222 A US3190222 A US 3190222A
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United States
Prior art keywords
fuze
casing
booster
wall
charge
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Expired - Lifetime
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US212517A
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English (en)
Inventor
Holmstrom Georg Henry Sixten
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Forsvarets Fabriksstyrelse
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Forsvarets Fabriksstyrelse
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Publication of US3190222A publication Critical patent/US3190222A/en
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Expired - Lifetime legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
    • F42C1/00—Impact fuzes, i.e. fuzes actuated only by ammunition impact
    • F42C1/02—Impact fuzes, i.e. fuzes actuated only by ammunition impact with firing-pin structurally combined with fuze
    • F42C1/04—Impact fuzes, i.e. fuzes actuated only by ammunition impact with firing-pin structurally combined with fuze operating by inertia of members on impact
    • F42C1/06—Impact fuzes, i.e. fuzes actuated only by ammunition impact with firing-pin structurally combined with fuze operating by inertia of members on impact for any direction of impact
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F42—AMMUNITION; BLASTING
    • F42C—AMMUNITION FUZES; ARMING OR SAFETY MEANS THEREFOR
    • F42C1/00—Impact fuzes, i.e. fuzes actuated only by ammunition impact
    • F42C1/10—Impact fuzes, i.e. fuzes actuated only by ammunition impact without firing-pin

Definitions

  • This invention relates to a highly sensitive top fuze for rotating shells as well as for non-rotating shells, and more particularly to shells having a shaped charge.
  • the invention has for its primary object to insure a safe and rapid ignition upon frontal as well as upon oblique impact of such a shell with a target and to reduce the dependency of the ignition on the angle of impact.
  • fuzes for ignition upon oblique impacts are generally based upon the use of firing pins or solid bodies, which upon impact have to be put in motion or moved aside, thus causing a delayed ignition.
  • pinless fuzes In order to reduce the time of ignition, pinless fuzes have been proposed, in the top of which an impact sensitive primer is arranged and being included merely in a thin-walled casing. Hitherto known fuzes of this kind however, are able to function only upon frontal contacts or close to frontal impacts.
  • the present invention is based on the well known principle of an impact-sensitive detonating cap being arranged in the top of the fuze, but constitutes a solution of the fuze problem which will eliminate the drawbacks mentioned above.
  • the invention primarily resides in the detonating cap forming a double-walled tubular casing, a part of which protrudes in front of the fuze body, said casing or at least the protruding part of it, being easily deformable, and including an impact-sensitive primer charge and having an auxiliary charge located behind the primer charge.
  • the casing is easily deformable implies that its walls should be so thin and also so soft as too be easily impressed, or so brittle as to be shattered into a number of small pieces upon the impact, which pieces penetrate the primer charge.
  • the ignition 3,19%,222 Patented June 22, 1965 of the primer charge is due to several causes. It is probably caused by the charge being compressed between the outer and inner wall of the casing and/or being ground against them, whereby an improved effect is obtained due to the rupture of the casing e.g. in the section of the transition to a strengthened part of its wall, which part 7 might be either a thickened wall or a supporting wall. It has however been proved that a layer of the primer charge should be thin if short time of ignition is to be obtained.
  • the distance between the outer and inner walls of the casing should be small.
  • the inner wall of the casing acts as an anvil upon impact.
  • Such an anvil effect is an explanation of the fact that the time of ignition is shortened if at least the free portion of the inner wall, abutting against the layer of the primer charge, is made thicker. It has resulted that the thickness of this wall portion need not essentially exceed the double thickness of the outer wall of the casing for the improvement, attainable in this way, to be utilized.
  • the increased thickness of the inner wall of the casing can be produced in a simple manner by combining an inner tube with an outer tube, with the latter having a flanged bottom pressed around the front end of the inner tube, so as to form a collar on the inside of the inner tube and in a suitable manner joining and tighten ing it to said inside.
  • the detonating cap may extend rearwardly to a substantial extent and it may be provided with so powerful an auxiliary charge, that the charge will directly detonate a bursting charge of a shell used with the fuze.
  • the fuze may be provided with a booster, arranged to be set ofi by the explosion of the auxiliary charge of the detonating cap.
  • the fuze is required to contain a device for mak ing it bore and trajectory safe. Accordingly, the present invention also refers to a fuze construction having such a device.
  • the detonating cap has a limited extension rearwardly so as to be embraced only by the forward portion of the fuze body, the rear portion of which contains a booster, which is slidable within the fuze body and, in a well known manner, provided with a propelling coil spring and a safety device, the booster being so arranged, that the forward end of its charge is embraced by the rear portion of the detonating cap, when the booster is brought to its forward position but shall be shielded from it by the forward end of the booster casing when the booster is brought to its rearward position.
  • This arrangement is an application of a well known principle of co-operation between a front charge and a rear charge of a fuze.
  • the fuze be closed, particularly when it contains a safety device.
  • this is efiected by a closing wall, transversely placed in the casing of the detonating cap at some distance from its front end.
  • the casing of the detonating cap consists of an inner tube, and an outer tube haying a bottom at its front end, such bottom being pressed into the end of the inner tube, so as to make its inside wall thicker as well as to form a desired closing wall.
  • Such a closing wall acts as a sup porting wall for the inner wall of the detonating cap, promoting its function of ignition and, when the above mentioned safety device is employed, this closing wall will cause the forward movement of the slidable booster to be dampened by air between it and the front end of the booster.
  • This dampening effect can be adjusted to the required time of bore safety by providing the front portion of the booster casing with escape channels or a suflicient allowance in relation to the inner wall of the casing of the detonating cap.
  • a packing means can be arranged between the booster casing and the casing of the detonating cap, such packing means being in the form of a packing ring or inserted silicon grease.
  • the portion of the detonating cap that is unprotected by the fuze body can be covered by a protecting hood, preferably being detachable by being thrown off.
  • a protecting hood preferably being detachable by being thrown off.
  • the same blocking means as those a ting upon the booster casing.
  • the detonating cap is slidably arranged in the fuze body, that is, mounted in a sleeve, in turn being slidable in the fuze body with such an axial motion margin that an essential portion of the fuze body will be blasted away before the slidable unit has been moved to its rearward position.
  • FIG. 1 is a longitudinal sectional view of a fuze in which the present invention is embodied
  • FIGS. 2 to 4 are respectively longitudinal sectional views of alternative forms of the fuze as constructed according to the present invention.
  • a fuze is therein shown, the same including a tubular fuze body 8, having a bottom screw plug 26, an impact-sensitive detonating cap generally indicated at 3 containing charges 2, 4, located in the forward end portion of the fuze body, and a booster disposed within the rear portion of the fuze body 8.
  • the front portion 11 and the rear portion 21 of the booster are kept together by a bushing 14.
  • the detonating cap 3 consists of a double-walled tubular casing 3a, the rear end of which is closed by a bottom 5.
  • the rear portion of the detonating cap is embraced by the fuze body 8, but its forward portion pro trudes in front of the fuze body.
  • the detonating cap contains an impact-sensitive primer charge 2 extending rearwardiy to about the front end of the fuze body.
  • the primer charge consists of lead azide and a minor portion of a sensitizing ingredient such as Tetrazen.
  • the detonating cap also includes an auxiliary charge 4, located behind the primer charge, and consisting of one or more layers of sensitive explosives, such as tetryl.
  • the casing 3a of the detonating cap 3 consists of a hardened aluminum alloy of good ductibility and strength. It preferably has a thin wall thickness so as to be deformed by slight impacts, the wall thickness being adapted to a required degree of sensitivity, so that ignition will be avoided upon impact with slight obstacles such as bushes.
  • the distance between the walls of the casing 3a is short and as a result the layer of the enclosed primer charge is thin, a good ignition result being obtained with a layer thickness of 1.5 mm.
  • the manufacture of the casing 3a will be simplified as well as the connection between the casing and a rear booster for transferring the ignition to the bursting charge of the shell used with the fuze.
  • the booster ill, 21 is slidably arranged in the rear portion of the fuze and has a transition charge It! in its forward portion 11 and an auxiliary charge in its rear portion, both charges consisting of relatively insensitive high explosives.
  • the forward end of the booster casing 11 has a thick cylindrical wall 7. When the booster is brought to its forward position, this wall extends so far into the detonating cap, that the charge 1% of the booster is partly embraced by the auxiliary charge 4 of the detonating cap enabling it to be ignited from the latter, the fuze being thus armed.
  • the front wall 7 is behind the auxiliary charge 4 of the detonating cap, thereby shielding the latter from the transition charge 10 of the booster. in this condition of the safety arrangement, the fuze will be unarmed.
  • the fuze is provided with a guide bushing 24 embracing the booster casing II, 21 and at its forward end 9 it also embraces the rear end of the detonating cap to which it is secured.
  • the rear end of the guide bushing houses a coil spring 22 arranged to move the booster casing 11, 21 forward.
  • the safety mechanism disposed within the fuze is adapted to operate according to a well known principle. In the arrangement shown in FIG. 1, it comprises blocking balls 16, a conical shoulder 17 on the outside of the bushing 14 and a blocking sleeve 18, slidable within the fuze body, said sleeve having an inwardly-directed flange 18a on its forward end and having a circumferential groove on its outside housing a friction spring 19.
  • the fuze body 8 has a circumferential shoulder 8a on its inner side, said shoulder constituting a stop face which co-operates with the forward end of the blocking sleeve 18.
  • the blocking sleeve 18 When the blocking sleeve 18 is in its forward position as shown by the disclosure of FIG. 1, its inwardly directed flange 18a will prevent the blocking balls 16, and as a consequence the booster casing 11, 21 as well as the bushing 24 from moving forwardly.
  • the blocking balls 16 constitute stop members behind said flange 18a as to prevent the blocking sleeve 13 from moving backwardly, as long as the blocking balls 16 are forced against the inner side of the blocking sleeve 18 by the conical shoulder 17 of the bushing 14.
  • the central portion of the guide bushing 24 is provided with axially-extending apertures 13 for the blocking balls 16 and the rear portion of the guide bushing is formed with a flange portion, the frontal surface of which constitutes a stop face co-opcrating with the rear end surface of the blocking sleeve 18.
  • the rear mouth opening of the fuze is closed by a thin disk 25.
  • the fuze is provided with a protective hood I at its forward end embracing the free portion of the detonating cap.
  • the protective hood is connected with a holding sleeve 12 by means of a lock device 6.
  • the rear portion of the holding sleeve 12 is provided with apertures 15, so as to be held by the blocking balls, 16.
  • the same safety device is used to keep the booster casing 11, 21, the protective hood I and the detonating cap 3 locked to the fuze body 8 before the firing of the shell and to release such members after the shell has been fired.
  • the operation of the safety device is as follows: Upon firing, set-back forces, acting on the fuze, immediately cause the booster casing 11, 21 and then, with some delay owing to the blocking effect of the blocking balls 16, the blocking sleeve 18 to be moved backwardly.
  • the blocking balls 16 are forced by the flange 18a of the blocking sleeve 18 against the booster casing 11, 21 above the conical shoulder 17 of the bushing 14, without entirely leaving the apertures 15 of the holding sleeve 12.
  • the blocking balls 15 are forced'outward back in full engagement with the apertures 15 of the holding sleeve 12 by the forward portion of the bushing 14.
  • the blocking balls now supported against the conical shoulder 17 of the bushing 14 are brought forwardly together with the booster casing, thereby being conveyed in the axial apertures 13 of the bushing 24. Then the booster casing is not prevented from reaching its forward position in which it is partly embraced by the detonating cap.
  • the blocking balls engage the holding sleeve 12, which consequently is forced ahead, taking the protective hood 1 with it.
  • the bushing 24 Before the shell is fired, the bushing 24 is held blocked in its rear position by the blocking balls 16, until the booster casing 1-1, 21 and the blocking sleeve 18 have moved rearwardly, so as to release the blocking balls from their blocking condition. After that the bushing 24 is prevented from forward movement merely by the action of the coil spring 22, the forward end of which presses against the rear end surface of the bushing 14. This action, however will cease in a very short time after the booster casing 11, 21 together with the bushing 14 has begun to move forward. Consequently the guide bushing 24 with little delay will move forward owing to its inertia, taking along with it the detonating cap 3, attached to it.
  • FIGS. 2 to 4 only the front portion of the fuze is shown, on an enlarged scale.
  • the detonating cap 3, its primer charge 2 and its auxiliary charge 4 are also arranged in the fuze body 8 as previously described.
  • the holding sleeve 11 is however, shown in its forward position and th protective hood is presumed to have been thrown off.
  • the forward portion of the inner wall of the casing 3a is twice as thick as the other wall portions of the casing and extends to about one-half the length of the layer of the primer charge 2.
  • the corresponding thicker wall portion has been created by the casing 3 being composed of an inner tube 28 and a concentrically arranged outer tube 25 the latter having a bottom flange, a portion of which is downturned by pressure into the inner tube and joined to the inside thereof to thereby form a collar inside of the inner tube.
  • the fuze shown in FIG. 4 represents a development of that shown in FIG. 3.
  • the outer tube is formed with a bottom wall without any central aperture and said bottom wall is pressed into the end of the inner tube, so as to form a collar 30, inside of the forward portion of the inner tube 28, as well as a closing wall 31.
  • This figure also shows a portion of the booster safety device of the kind described above, the casing of that booster being in its forward position and the fuze thereby being armed.
  • the closing wall 3 1 is at such a distance from the end of the fuze that the front end 7 of the booster casing 11 just reaches this wall.
  • the closing wall 31 is of particular significance in fuzes having a safety device of this kind.
  • the air enclosed between this wall and the end wall 7 can be utilized for dampening the forward movement of the booster casing 11.
  • the booster casing has a certain allowance in the fuze, a too-hard dampening effect will be prevented, that is if the all-owance is properly adjusted and if necessary, supplemented with external longitudinal grooves, the dampening effeet can be adapted to the required time of trajectory safety.
  • a closing wall can be arranged in other ways than is shown in FIG. 4 and it is not necessary to make'the inner wall of the detonating cap thicker at its front end at the same time.
  • the closing wall should, however, be placed at some distance from the end of the detonating cap, preferably near its middle plane, so as to be able to co-operate with an existing booster safety device.
  • An impact-sensitive top fuze having a body pro vided with a detonating cap in it, said cap consisting of an annular casing protruding from the fuze body, the protruding portion of the casing being readily deformable, said c-asing having an inner and an outer tubular wall, which walls define an annular space between them, an annular wall at each end of the casing for closing said space, an impact-sensitive primer charge occupying the forward portion of said space, and an auxiliary charge occupying the remaining portion of said space.
  • an impact-sensitive top fuze as provided for in claim 1, wherein the casing is composed of an inner tube and an outer tube, said outer tube being shaped with an inwardly-directed cup at its forward end, said cup fitting within the forward end of the inner tube to thereby form a collar around the inside of the inner tube at its forward end and to provide a transverse closing wall located to the rear of said forward end.
  • An impact-sensitive top fuze having a body and an annular impact-sensitive detonating cap protruding from the fuze body, the rear portion of said annular cap being disposed in the forward portion of the fuze body, a booster slidably arranged in the rear portion of the fuze body, said booster being biased forwardly by a propelling coil spring blocking means preventing forward movement of the booster, inertia-actuated means co-operating with the blocking mean-s for bringing the blocking means out of blocking position upon firing,
  • the forward end of the booster charge being embraced by the rear portion of the annular detonating cap, when the booster is moved to its forward position, the booster having a charge and having a for-ward end wall shielding its charge from the rear portion of the annular detonating cap when the booster is rearwardly disposed.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Air Bags (AREA)
  • Vibration Dampers (AREA)
  • Braking Systems And Boosters (AREA)
US212517A 1961-10-31 1962-07-26 Impact sensitive top fuze Expired - Lifetime US3190222A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE1082161 1961-10-31

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US3190222A true US3190222A (en) 1965-06-22

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US212517A Expired - Lifetime US3190222A (en) 1961-10-31 1962-07-26 Impact sensitive top fuze

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US (1) US3190222A (hu)
BE (1) BE615565A (hu)
CH (1) CH386294A (hu)
DE (1) DE1181095B (hu)
GB (1) GB955206A (hu)
NL (2) NL128333C (hu)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3366059A (en) * 1967-01-09 1968-01-30 Avco Corp Fuze for spin stabilized projectiles
US3472167A (en) * 1967-01-02 1969-10-14 Forsvarets Fabriksverk Safety device for nose fuze
US9453531B2 (en) 2013-08-26 2016-09-27 Roller Bearing Company Of America, Inc. Integrated bearing assemblies for guided attack rockets
CN113607013A (zh) * 2020-10-27 2021-11-05 湖南华峰新宇电子有限公司 一种具有防尘功能的引信控制开关

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1455741A (en) * 1922-06-09 1923-05-15 Bofors Ab Fuse
US2705921A (en) * 1949-12-15 1955-04-12 Jr John W Moseman Fuze for non-rotating shaped charge projectiles
US2737888A (en) * 1952-01-25 1956-03-13 Energa Projectile equipped with a safety device
US2780995A (en) * 1952-07-09 1957-02-12 Bombrini Parodi Delfino S P A Projectile with extra-sensitive head
US2931039A (en) * 1955-08-29 1960-04-05 Olin Mathieson Cartridge firing apparatus

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR516458A (fr) * 1918-07-18 1921-04-19 Joseph Capo Blanch Fusée
GB136318A (en) * 1919-01-02 1919-12-18 Arthur Adelman Improvements in Detonating Fuses for Projectiles.
US2424970A (en) * 1940-01-19 1947-08-05 Joseph H Church Explosive projectile
NL101335C (hu) * 1957-02-26

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1455741A (en) * 1922-06-09 1923-05-15 Bofors Ab Fuse
US2705921A (en) * 1949-12-15 1955-04-12 Jr John W Moseman Fuze for non-rotating shaped charge projectiles
US2737888A (en) * 1952-01-25 1956-03-13 Energa Projectile equipped with a safety device
US2780995A (en) * 1952-07-09 1957-02-12 Bombrini Parodi Delfino S P A Projectile with extra-sensitive head
US2931039A (en) * 1955-08-29 1960-04-05 Olin Mathieson Cartridge firing apparatus

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3472167A (en) * 1967-01-02 1969-10-14 Forsvarets Fabriksverk Safety device for nose fuze
US3366059A (en) * 1967-01-09 1968-01-30 Avco Corp Fuze for spin stabilized projectiles
US9453531B2 (en) 2013-08-26 2016-09-27 Roller Bearing Company Of America, Inc. Integrated bearing assemblies for guided attack rockets
CN113607013A (zh) * 2020-10-27 2021-11-05 湖南华峰新宇电子有限公司 一种具有防尘功能的引信控制开关

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Publication number Publication date
NL128333C (hu)
CH386294A (fr) 1964-12-31
DE1181095B (de) 1964-11-05
NL280653A (hu)
BE615565A (fr) 1962-07-16
GB955206A (en) 1964-04-15

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