FUSE ASSEMBLY FOR A MUNITION

Abstract

A fuse mechanism for e.g. a pyrotechnic grenade in which a spring loaded striker lever (31) is blocked via a cammed surface (22) of a safety lever (21) comprising a handle. (25). Release of the handle (25) enables deployment of the fuse assembly. Spring-loaded striker lever (31) is urged upwards by the force of torsion spring (38). Contact between the free end (34) of the striker lever (31) exerts a rotational force on cammed portion (22). The safety lever (21) rotates away from the body of the munition (20). Rapid upward movement of the striker lever (31) is prevented at this stage by contact of the free end (34) with the cammed portion (22). Further rotation of the safety lever (21) occurs until point where the cammed portion (22) is no longer in contact with the striker lever. Ultimately, once the safety lever (21) has rotated beyond a certain extent, the free end of the striker lever (31) is no longer in contact with the cammed portion (22), and the striker lever is urged rapidly away from the body of the munition (20).

Claims

1. A fuse assembly for igniting a charge, comprising a) a fuse housing (28); b) a safety lever (21) pivotally attached to the fuse housing (28), said safety lever (21) having a handle portion (25) and a cammed portion (22) generally disposed about a first pivot point (23); c) a spring loaded striker lever (31) pivotally attached to the fuse housing (28), having a second pivot point (32) provided towards a first end (33) and a second free end (34), the striker lever (31) being adapted to receive the pull-wire (36) of a pull-wire igniter; wherein in a first configuration, the free end (34) of the spring loaded striker lever (31) is in contact with the cammed portion (22) of the safety lever (21) holding the striker lever (31) in position, such that rotation of the safety lever (21) away from the fuse housing (28) reduces contact between the free end (34) and the cammed portion (22), allowing the spring loaded striker lever (21) to rotate away from the fuse housing (28).

2. A fuse assembly according to claim 1, wherein the striker lever (31) is provided with a pull-wire (36).

3. A fuse assembly according to claim 2, wherein said pull-wire (36) extends through a hole in a metal cup containing a pyrotechnic mixture (43).

4. A fuse assembly according to claim 1, wherein the cammed portion (22) is generally in the form of a spiral disposed about the pivot point (23).

5. A fuse assembly according to claim 1, wherein the cammed portion (22) features a step.

6. A fuse assembly according to claim 1, wherein there is provided a safety pin (30).

7. A fuse assembly according to claim 1, wherein the spring loaded striker lever (31) is provided with a torsion spring (38).

8. A fuse assembly according to claim 1, wherein the second free end (34) of spring loaded striker lever (31) is rounded in profile.

9. A munition provided with a fuse assembly as claimed in claim 1.

10. A munition according to claim 9 which is adapted to be thrown.

11. A munition according to claim 9 which is a pyrotechnic.

12. A munition according to claim 11 which is a smoke generating device.

13. (canceled)

Description

DESCRIPTION OF THE FIGURES

[0013] FIG. 1 is a smoke grenade of known type.

[0014] FIG. 2 is a section view of a fuse according to one embodiment of the invention, prior to use.

[0015] FIG. 3 is a section view of a fuse according to one embodiment of the invention, immediately after use.

[0016] FIG. 4 is a section view of a fuse according to one embodiment of the invention, subsequently after use.

[0017] FIG. 5 is a section view of a fuse according to one embodiment of the invention, subsequently after use.

[0018] FIG. 6 is a section view of a munition, incorporating a fuse according to one embodiment of the invention.

SUMMARY OF THE INVENTION

[0019] According to a first embodiment, there is provided a fuse assembly for igniting a charge, comprising [0020] a) a fuse housing (28); [0021] b) a safety lever (21) pivotally attached to the fuse housing (28), said safety lever (21) having a handle portion (25) and a cammed portion (22) generally disposed about a first pivot point (23); [0022] c) a spring loaded striker lever (31) pivotally attached to the fuse housing (28), having a pivot point (32) provided towards a first end (33) and a second free end (34), the striker lever (31) being adapted to receive the pull-wire (36) of a pull-wire igniter; [0023] wherein [0024] in a first configuration, the free end (34) of the spring loaded striker lever (31) is in contact with the cammed portion (22) of the safety lever (21) holding the striker lever (31) in position, such that rotation of the safety lever (21) away from the fuse housing (28) reduces contact between the free end (34) and the cammed portion (22), allowing the spring loaded striker lever (21) to rotate away from the fuse housing (28).

DETAILED DESCRIPTION

[0025] FIG. 2 shows an embodiment of the invention, with the fuse assembly attached to a munition (20). Safety lever (21) includes a cammed portion (22) generally disposed about a seat (23). Extending horizontally from the cammed portion is connecting arm (24), which connects to a handle (25), which is generally perpendicular to the connecting arm (24).

[0026] The safety lever (21) is pivotally attached via pivot (27) sitting within seat (23) to fuse housing (28). The safety lever (21) is held in position by safety pin (30), which passes through the fuse housing (28), and prevents rotation of safety lever (21) about pivot (27).

[0027] Striker lever (31) is of generally elongate form, and is provided with a pivot hole (32) towards a first pivoted end (33) and a second free end (34). In the embodiment shown, second free end (34) has a rounded profile.

[0028] The striker lever (31) is pivotally attached via pivot (37) passing through pivot hole (32) to fuse housing (28). A torsion spring (38) is wound about pivot (37), and in the configuration shown the torsion spring (38) is held under compression. Striker lever and safety lever (21) pivot about separate points, and in opposite directions. The second free end (34) of the striker lever (31) is in contact with cammed portion (22) of the safety lever, which prevents rotation of striker lever (31) in an upwards direction.

[0029] A metal wire (36) is attached at one end to a stud (40) provided on the upper surface of striker lever (31). The wire passes through a hole in a metal cup (41), and has a coiled portion (42) which sits within or below the metal cup (41). Metal cup (41) contains a pyrotechnic mixture (43). The body of the device to which the assembly is attached contains a primer composition (44) and pyrotechnic charge (45).

[0030] In use, the operator holds handle (25) against the body of the munition (20), and removes the safety pin (30). The munition is thrown or released, which releases the restraining pressure on handle (25).

[0031] Removal of the safety pin (30) and release of the handle (25) enables deployment of the fuse assembly, as shown in FIG. 3.

[0032] Spring-loaded striker lever (31) is urged upwards by the force of torsion spring (38). Contact between the free end (34) of the striker lever (31) exerts a rotational force on cammed portion (22). The safety lever (21) rotates away from the body of the munition (20). Rapid upward movement of the striker lever (31) is prevented at this stage by contact of the free end (34) with the cammed portion (22).

[0033] Further rotation of the safety lever (21) occurs until point A where the cammed portion (22) is no longer in contact with the striker lever. This is shown in FIG. 4.

[0034] Ultimately, once the safety lever (21) has rotated beyond a certain extent, the free end of the striker lever (31) is no longer in contact with the cammed portion (22), and the striker lever is urged rapidly away from the body of the munition (20). This pulls the coiled portion of the wire through the hole in the metal cup (41). The heat generated causes the pyrotechnic composition (43) to ignite, and ultimately results in ignition of the primer (44) and pyrotechnic charge (45). The safety lever (21) is able to detach from the device. This is shown in FIG. 5.

[0035] It has been found that the cammed profile of the safety lever results in the constant contact between cam and striker lever (31) during the rotation of the safety lever (21), holding the striker lever (31) in position until the point when the striker lever (31) is suddenly released. The sudden and rapid release of the striker lever (31) rather than gradual release as seen in known devices allows for greater heat generation through friction which allows superior ignition of the fuse mechanism and a lower proportion of fuse mechanism failures and a lower kick experienced by the operator. This invention has the added advantage that the rapid release of the striker lever at point A is not dependant on deployment of how the device is deployed, resulting in fewer operator error malfunctions of the munitions.

[0036] The fuse is applicable to any type of munition, particularly those which are thrown by hand. Accordingly, the invention also relates to a munition featuring a fuse of the type described. Such munitions include smoke devices, flash devices, explosive devices, tear gas devices, and whistle or other noise-making devices.