US3557701A

US3557701A - Hand-grenade fuze

Info

Publication number: US3557701A
Application number: US797033A
Authority: US
Inventors: Claes G Arnell
Original assignee: Foersvarets Fabriksverk
Current assignee: Foersvarets Fabriksverk
Priority date: 1969-02-05
Filing date: 1969-02-06
Publication date: 1971-01-26
Anticipated expiration: 1988-01-26
Also published as: GB1218884A; NL6901794A; CH478398A; FR2021274A5; DE1905953A1

Abstract

A hand grenade, land mine or the like, of the type which comprises a striker, provided with an ignition pin, partly enclosed by a sleeve in the bottom of which a primer, such as an ignition cap, is located, the parts are supported by two conical end walls in a fuze body member and locked by a number of balls or other similar members. The missile may be provided with a delay mechanism, such as a delay charge located in an end part of the missle, the end part is rotatable relative to the rest of the missile in order to adjust the delay time.

Description

i vUnited States Patent Inventor Claes G. Arnell Torshalla, Sweden Appl. No. 797,033

Filed Feb. 6, 1969 Patented Jan. 26, 1971 Assignee Forsvarets Fabriksverk Eskilstuna, Sweden a corporation of Sweden HAND-GRENADE FUZE 4 Claims, 3 Drawing Figs. I

US. Cl 102/76, 102164, 102/852, 102/85.6 Int. Cl ..F42b 27/00, F42c 15/00 Field of Search 102/64, 70-

72(except 70.2), 76, 85-856 References Cited Primary ExaminerBenjamin A. Borchelt Assistant Examiner-Charles T. Jordan Att0rneyEric Y. Munson ABSTRACT: A hand grenade, land mine or the like, of the type which comprises a striker, provided with an ignition pin, partly enclosed by a sleeve in the bottom of which a primer, such as an ignition cap, is located, the parts are supported by two conical end walls in a fuze body member and locked by a number of balls or other similar members. The missile may be provided with a delay mechanism, such as a delay charge located in an end part of the missle, the end part is rotatable relative to the rest of the missile in order to adjust the delay time.

PATENTED mm IN VEN'I'OR.

67-386 ol )1 A r11.

ATENTEU JAH2 61971 SHEET 3 0F 3 HAND-GRENADE FUZE The present invention relates to a hand grenade, a land mine or the like, of the type whichcomprises a striker, provided with an ignition pin, partly enclosed by a sleeve in the bottom of which a primer, such as an ignition cap, is located, said parts being supported by two conical end walls in a fuze body member and locked by a number of balls or other, similar members. Further, the missile may be provided with a delay mechanism, such as a delay charge located in an end part of the missile, said end part being rotatable relative to the rest of the missile in order to adjust the delay time.

It is a general desire that missiles of the above type should be adaptable to perform a number of different functions, so that one type of missile can be used for different purposes.

Sometimes, instantaneous detonation is wanted and sometimes a detonation delayed by a few seconds is desired. The delay chargefor obtaining the delay comprises a combustion path with some pyrotechnical material, such as gunpowder. By the adjustment for different delay times, the delay path is shortened or lengthened.

When a projectile of the type indicated is to be used as a hand grenade which explodes upon impact, it must be brought to explode independent of which side of the missile first strikes the target. In other words, it must be sensitive for all types of impact. Because of the conical end walls supporting the sleeve with the striker and the ignition cap, the ignition pin of the striker will be pressed against the ignition cap even when the grenade is moving in a direction before impact which makes a right angle with the direction of movement of the striker.

A general problem in connection with missiles of such universal use is to provide a satisfactory safety device which is not too complicated.

In the grenade according to the invention, the striker is locked for movement in said sleeve by a number of balls. or other, similar locking means between the sleeve and the striker, said locking means being movable from an active, locking positiomwhere they keep said striker and said sleeve against relative movement, to an inactive position, in which such movement is allowed, there being a blocking pin extending longitudinally of said striker and sleeve, said blocking pin engaging said locking means and keeping them in their active position, and a spring tending to withdraw said blocking pin out of engagement with said locking means.

According to the invention, there is a blocking body member mounted in a chamber in an enlarged, outer part of said pin, said blocking body member being retained in an active, blocking position by a permanent magnet and preventing said withdrawal of said pin by engaging an inner wall surface of said fuze body member through intermediate blocking balls, and being movable to an inactive position by the centrifugal force or acceleration force, caused by a throw movement of the grenade, where it is caught and retained by a second permanent magnet, and where said, blocking pin is free to be withdrawn by said spring.

According to a further development of the invention, said blocking body member is a steel ball movable axially in an axial cylindrical chamber in an enlarged end of said pin, said chamber having end walls in which'said permanent magnets are mounted, said intermediate blocking balls being movable in radial bores of the mantle wall of said chamber and engaging an annular shoulder portion forming one end wall of an annular groove in the inner wall surface of said fuze body member, said groove having also a middle shoulder portion dividing the groove in a deeper part and ashallower part, said shallow part registering with said intermediate blocking balls when said pin is in its safety position, where the operation of said striker is prevented, and where said intermediate blocking balls prevent said blocking body member to be released from its inactive position, and said intermediate blocking balls registering with said deeper part when said pin is manually pressed further inwards into said striker, to a temporary position, in which said intermediate blocking balls are free to move radially outwards, out of the path of movement of said blocking body member, said member being then free to move to its inactive position under the influence of the centrifugal or acceleration force.

A grenade provided with a safety device according to the ini vention can easily be adapted for many different functions. Still, the safety devicei is very effective and prevents unintended explosion in all kinds of operation. Further, the grenade is easy to adjust for said different functions. It is also simple and reliable and inexpensive to manufacture.

These and other advantages of the present invention will be apparent from the following detailed description in which references are made to the accompanying drawings, illustrating one embodiment of the invention by way of example.

FIG. 1 illustrates a longitudinal section of the grenade in safety condition and with a safety catch pin inserted.

FIG. 2 illustrates a similar longitudinal section of the grenade in a condition where the striker is unlocked and the I safety catch pin is pulled out.

FIG. 3 shows an exploded view of the grenade, some of the parts illustrated being shown partly in section.

The outer envelope of the grenade comprises an egg-shaped shell 1. To the bottom part of 'said shell there is rotatably mounted a circular block 3. Between said block 3 and the rest of the shell there is a part 2 formed as a conical collar. The collar 2 surrounds partly the block 3 which serves as a timing device and which has a semicircular channel 22 for a delay combustion charge. Between the block 3 and the collar 2 there is a disc 4 serving as a holder for two

combustible charges

20 and 20a. Between the upper part of the shell 1 and the disc 4 there is located a bodymember 5 for a fuze. Said body member has in its upper part a big axial bore in which a safety catch member 7 serving as a throw safety catch is slidable. The safety catch member 7 is provided with a chamber 8,, in the upper end, in the end walls of which two

permanent magnets

10 and 10a are inserted. In the chamber 8 there is a blocking body member in the formof a ball 9 which has a slightly less diameter than the circular chamber 8. In the cylin-I drical wall of the chamber 8 there is a number of radially directed, through bores 8a. Balls 11 serving as intermediate blocking means, are inserted in said bores 80. Outside said bores 8a there is an annular groove 12 in the inner wall of the, fuze body member 5. The safety catch member 7 is influenced]; by a helical spring 18 which tends to press the member 7 out-E wards. A pin 28 is inserted in bores la in the shell 1 and 7a in the member 7 so as to keep the member 7 locked in place in a safety position (FIG. 1).

The fuze body member 5 has also a lower chamber 6 with

conical end walls

60 and 6b. Between said conical surfaces there is a striker 15 inserted, which is partly enclosed in an outer sleeve 16. The striker 15 is at its bottom end provided with an ignition pin 15a and at its top end with a semispherical mushroom head 15b. Immediately below the mushroom head 15b there is a deep groove 15c which is excentrical with respect to the longitudinal axis of the striker l5 and which at one side (to the left in the drawing) opens into an axial, central bore 19 provided in the striker 15. In the groove there is a locking spring 13 consisting of a helical steel strip or the like. Below said groove 15c there is a pair of radially directed through holes lsLwhich extend into the axial bore 19 and in which locking members, such as balls 14, are inserted and displaceable in a radial direction.

At the inner mantle wall of the outer sleeve 16 there is an annular groove 16a registering with said locking members 14. In the bottom part of the outer sleeve 16 there is a primer or ignition cap 21. The outer surface 16b of the bottom part of the outer sleeve 16 is, as shown, semispherical, corresponding to the shape of the mushroom head 15b.

The ignition cap 21 communicates with the semicircular delay combustion composition 22a through

openings

6c and 4a in the conical surface 6b and the disc 4, respectively, in which rapid combustion charges 20a and 20b, respectively, are located, and a radial groove 33 with a combustion charge 220. In a threaded, central bore in the bottom block 3 there is a hollow, axially directed screw 23. In its outer end, said screw is provided with a number of radially directed bores 23a, the openings of which are covered by an elastic packing ring 24. Said ring 24 acts as a valve for the gunpowder gases from the

charges

21, 20a, 20b, and 22a and prevents a too rapid combustion of the delay composition 22a. The delay composition 22a communicates over a rapid combustion charge 20 and a detonator 25 with the explosive charge 26.

In a radially directed channel 27 in the bottom block 3, there is a number of balls 27a which are pressed outwardly against an annular groove 2a of the conical collar 2 by means of the conical end 23a of the screw 23, in order to avoid looseness and provide a suitable amount of friction between the collar 2 and the block 3. I

In a safety condition, the

parts

3 and 2 are kept in the correct angular position in relation to each other by means of a ball 3a which is displaceably kept in a bore 3b in the block 3 and under the action of a helical spring 30 is pressed into a recess 3Lat the inner surface of the collar 2. The angular end positions of the block 3 in the collar 2 are defined by a stopping pin (not shown) in one of said parts which is received in a groove in the other part.

The grenade is sealed for moisture by means of a number of packing rings such as the packing rings 2b between the parts 1 and 2 and the packing ring 3e between the

parts

2 and 3. There are also other packing rings between the parts 1 and 5 and between 5 and 7 but for the sake of simplicity those packing rings are not shown in the drawings.

In operation, the block 3 is first rotated to the angular position relative to the collar 2 which corresponds to the wanted manner of operation. The positionsto which said block can be turned are:

Safety position (S);

Delay position (T 1 4 seconds); and

Instantaneous detonation ((1 After the adjustment of tlEblock 3 to the wanted position the safety pin 28 is removed and the safety member 7 is pressed into the shell about 1 centimeter. The consequence of that is that the balls 1 1, from the position illustrated in FIG. 1, will fall downwards and outwards in the annular groove 12 in the inner wall of the fuze body member 5 and then the ball 9 will be free for movement. If the operator now swings his arm, the ball 9 will be actuated by a centrifugal force and free itself from the lower permanent magnet 10, and be thrown out so that it is caught by the upper permanent magnet 10a. The blocking balls 11 will now fall inwards into the space where the ball 3 has been, and they will now be retained in that position either by the magnetical force of the bottom permanent magnet 10 or by the magnetical force from the ball 9, which is magnetized by the upper permanent magnet 100. This condition is illustrated in FIG. 2. When the grenade is thrown away and, consequently, the safety body member 7 is released from the finger pressure of the operator, said body member 7 will be pressed outwards by the spring 18, whereby the rod 17 will be totally moved out of the bore in the striker 15. The safety member 7 is perhaps thrown out from the grenade entirely, in which case it falls to the ground.

When the rod 17 is removed from the bore 19 in the striker 15, the balls 14 are pressed inwards under the bottom end of the rod 17, as shown in FIG. 2 and the striker is now free to be moved, so that the ignition pin 15a engages the ignition cap 21 in the outer sleeve 16 when the grenade strikes the target. This occurs independent of which surface of the grenade receives the impact. If the upper end, as shown in the drawing, hits the target, the inertia of the sleeve 16 will cause the sleeve to be moved against said upper end of the grenade. If the lower end, as shown in the drawing, hits the target first, the inertia of the striker 15 will cause said movement to occur. If the side surface of the grenade hits the target first, the striker will be pressed further into the sleeve 16 by the

conical surfaces

6a and 6b so that said movement will occur.

The different manipulations for the wanted functions may be briefly described as follows:

EXPLOSION UPON lMPACT Turn block 3 to position In this position the charge 20 is in alignment with the outer end of the radial channel 33. Press the safety member 7 down and throw away. The striker is operated upon impact and the explosion occurs immediately.

FLIGHT DETONATION DELAYED DETONATION UPON IMPACT Adjust block 3 to delay position (T l 4 seconds). Press down the safety member 7 and throw away. The safety member 7 is then pressed out partly or entirely by the spring 18. The striker is operated upon impact, and the explosion occurs after 1 4 seconds according to the position to which the block 3 has been turned.

AMIBUSH MINE Adjust block 3 to position S. Press down the safety member 7. Make a throw movement. Remove the safety member totally. Then turn the block 3 to a new position (Delay position, T l 4 seconds). Put the mine carefully where the ambush should be laid. The striker will be operated by a violent movement or impact, and the explosion follows after 1 4 seconds according to the adjustment of the block 3.

TREAD MINE Turn block 3 to position S. Push down the safety member. Make a throw movement. Pull out the safety member about 15 mm. Turn the block 3 to delay position (T l 4 seconds).

Put the mine carefully where it should be located with the safety member 7 upwards. The striker will be operated when the safety member is treaded on and pressed further into the grenade. (When the safety member 7 is pulled out about l5 mm., the spring 13 will move into the opening 19 below the bottom end of the rod 17. When the safety member 7 is pressed down as described, the bottom end of the rod 17 is 1 pressed against the spring 13 and the striker 15 with the ignition pin 15a will be pressed to engagement with the ignition cap 21). The explosion occurs after 1 4 seconds after that the safety member is treaded on, according to the angular position of the block 3.

The invention is not limited to the embodiment described. Thus, it is possible to make modifications, for example by locating the permanent magnets otherwise or by making the delay device and the direction of movement of the safety member 7 otherwise than described. A conventional rubbing ignitor can also be used instead of the ignition pin 15a.

Iclaim:

1. In a hand grenade or similar missile, an outer shell (1), an explosive charge (26) inside said shell and a fuze for igniting said charge, said fuze comprising a hollow fuze body member (5), a chamber (6) inside said body member having conical end surfaces (6a,6b), a sleeve (16) located within said chamber and engaging one (6b) of said conical end surfaces, a striker (15) located in said chamber in a telescopic relationship inside said sleeve (16) and engaging the other (6a) of said conical end surfaces (611,60), an ignition cap (21) mounted in said sleeve (16), an ignition pin (15a) mounted on said striker (15) in alignment with said ignition cap (21), locking means (14) between said sleeve (16) and said striker (15), said locking means (14) movable from an active, lockin position,

where they keep said striker and said sleeve locked against relative movement, to an inactive position in which they allow such movement, a blocking pin (17) extending longitudinally of said striker l5) and sleeve (16), said blocking pin engaging said locking means (14) and keeping them in their active position, and a spring (18) tending to withdraw said blocking pin (17) out of engagement with said locking means 14), wherein a blocking body member (9) is mounted in a chamber (8) in an enlarged, outer part (7) of said blocking pin (17 said blocking body member (9) being retained in an active, blocking position by a permanent magnet (10) where it prevents said withdrawal of said blocking pin 17) by engaging an inner wall surface (12d) of said fuze body member (5) through intermediate blocking balls (11), and being movable to an inactive position by the centrifugal force or acceleration force, caused by a throw movement of the grenade, where it is caught and retained by a second permanent magnet (10a) and where said blocking pin (17) is free to be withdrawn by said spring (18).

2. A hand grenade according to claim 1, wherein said blocking body member is a steel ball (9) movably axially in an axial cylindrical chamber (8) in an enlarged end (7 of said blocking pin (17), said chamber having end walls in which said permanent magnets (10,100) are mounted, said intermediate blocking balls (11) being movable in radial bores (8a) of the mantle wall of said chamber (8) and engaging an annular shoulder portion (120) forming one end wall of an annular groove (12) in the inner wall surface of said fuze body member (5), said groove having also a middle shoulder portion (12b) dividing the groove in a deeper part (12c) and a shallower part (12d), said shallow part (12d) registering with said intermediate blocking balls l1 when said blocking pin is in its safety position, where the operation of said striker 15) is prevented, and where said intermediate blocking balls (11) prevent said blocking body member (9) to be released from its inactive position, and said intermediate blocking balls (11) registering with said deeper part (12c) when said blocking pin (17) is manually pressed further inwards into said striker (15), to a temporary position, in which said intermediate blocking balls (11) are free to move radially outwards, out of the path of movement of said blocking body member (9), said member (9) being then free to:move.= to its inactive position under the influence of the centrifugal or acceleration force.

3. In a hand grenade according to claim 1, an intermediate combustion charge (22a) between said ignition cap (21) and said explosive charge (26), said intermediate charge being adjustable in length to allow for different delay times between operation of said striker (l5) and explosion of the explosive charge (26).

4 In a hand grenade according to claim 1, a latch spring (13) in said striker (15), said latch spring cooperating with the end of said blocking pin (17) when the blocking pin has been pulled out a predetermined distance to a position, from which a repeated inward movement of said blocking pin (17) results in a corresponding movement of said striker (l5) and engagement of said ignition pin (15a), with said ignition cap (21).

Claims

1. In a hand grenade or similar missile, an outer shell (1), an explosive charge (26) inside said shell and a fuze for igniting said charge, said fuze comprising a hollow fuze body member (5), a chamber (6) inside said body member having conical end surfaces (6a,6b), a sleeve (16) located within said chamber and engaging one (6b) of said conical end surfaces, a striker (15) located in said chamber in a telescopic relationship inside said sleeve (16) and engaging the other (6a) of said conical end surfaces (6a,6a), an ignition cap (21) mounted in said sleeve (16), an ignition pin (15a) mounted on said striker (15) in alignment with said ignition cap (21), locking means (14) between said sleeve (16) and said striker (15), said locking means (14) movable from an active, lockin position, where they keep said striker and said sleeve locked against relative movement, to an inactive position in which they allow such movement, a blocking pin (17) extending longitudinally of said striker (15) and sleeve (16), said blocking pin engaging said locking means (14) and keeping them in their active position, and a spring (18) tending to withdraw said blocking pin (17) out of engagement with said locking means (14), wherein a blocking body member (9) is mounted in a chamber (8) in an enlarged, outer part (7) of said blocking pin (17), said blocking body member (9) being retained in an active, blocking position by a permanent magnet (10) where it prevents said withdrawal of said blocking pin (17) by engaging an inner wall surface (12d) of said fuze body member (5) through intermediate blocking balls (11), and being movable to an inactive position by the centrifugal force or acceleration force, caused by a throw movement of the grenade, where it is caught and retained by a second permanent magnet (10a) and where said blocking pin (17) is free to be withdrawn by said spring (18).

2. A hand grenade according to claim 1, wherein said blocking body member is a steel ball (9) movably axially in an axial cylindrical chamber (8) in an enlarged end (7) of said blocking pin (17), said chamber having end walls in which said permanent magnets (10,10a) are mounted, said intermediate blocking balls (11) being movable in radial bores (8a) of the mantle wall of said chamber (8) and engaging an annular shoulder portion (12a) forming one end wall of an annular groove (12) in the inner wall surface of said fuze body member (5), said groove having also a middle shoulder portion (12b) dividing the groove in a deeper part (12c) and a shallower part (12d), said shallow part (12d) registering with said intermediate blocking balls (11) when said blocking pin is in its safety position, where the operation of said striker (15) is prevented, and where said intermediate blocking balls (11) prevent said blocking body member (9) to be released from its inactive position, and said intermediate blocking balls (11) registering with said deeper part (12c) when said blocking pin (17) is manually pressed further inwards into said striker (15), to a temporary position, in which said intermediate blocking balls (11) are free to move radially outwards, out of the path of movement of said blocking body member (9), said member (9) being then free to move to its inactive position under the influence of the centrifugal or acceleration force.

3. In a hand grenade according to claim 1, an intermediate combustion charge (22a) between said ignition cap (21) and said explosive charge (26), said intermediate charge being adjustable in length to allow for different delay times between operation of said striker (15) and explosion of the explosive charge (26).

4. In a hand grenade according to claim 1, a latch spring (13) in said striker (15), said latch spring cooperating with the end of said blocking pin (17) when the blocking pin has been pulled out a predetermined distance to a position, from which a repeated inward movement of said blocking pin (17) results in a corresponding movement of said striker (15) and engagement of said ignition pin (15a), with said ignition cap (21).