The invention relates to the field of diversionary munitions. More specifically, the invention comprises a hand grenade having the ability to fire multiple separate charges in a desired time-delayed sequence.
In many law enforcement and tactical military situations it is desirable to provide a diversionary device. An example of such a device is a “flash/bang” grenade (sometimes also know as a “stun grenade”). A flash/bang grenade is typically armed and thrown in the same manner as a fragmentation grenade (a “frag”). However, unlike a frag grenade, a flash/bang device does not produce flying fragments. Instead, it produces a loud noise and typically a bright flash of light (though some produce comparatively little light).
The U.S. Army's M84 stun grenade produces a sound level sufficient to cause a temporary loss of hearing and impairment of balance. It produces a flash bright enough to impair vision for over 5 seconds, as well, as producing a persistent afterimage that may impair the aiming of a weapon for up to 30 seconds.
Stun grenades are often used when breaching a door and securing a room that is suspected to contain hostile occupants. The door is breached and a stun grenade is thrown into the room. Immediately after the detonation of the stun grenade an infiltration team storms into the room and engages the occupants. The idea is for the engagement to commence and be completed before the occupants have recovered from the effects of the flash/bang.
In other instances a flash/bang is used as a misdirection device. For example, a patrol trying to flank the right side of an enemy position might toss a flash/bang to the left. Upon the detonation of the diversionary device the patrol would then maneuver around the right. Unfortunately, however, traditional devices such as the M84 are only marginally effective as a diversionary device. They produce only a single report. In the diversionary role, the detonation may be too far from the enemy position to impair hearing or sight. Though it attracts attention, it only does so for a short while.
A better device would attract attention for a longer interval. It is also desirable for the device to create some doubt as to its nature. If, for example, the engaged adversary questions whether the flash/bang is a single explosion or may instead represent sustained fire from another weapon-holder, a real tactical advantage is created. The present invention provides this functionality.
The present invention comprises a diversionary device capable of providing multiple discharges according to a prescribed time schedule. The device preferably assumes the same general form as a prior art stun grenade, including a safety pin that is pulled to arm the device and a spring-biased lever that is released when the device is deployed.
Timing is provided by a timing drum moving at a controlled rate. The controlled rate may be provided by a piston moving through a metering fluid. The piston may include one or more metering orifices that control its rate of travel.
Multiple firing chambers are included in the device, each of which can receive a cartridge to be detonated. Each firing chamber is provided with a corresponding spring-loaded striker positioned to detonate a cartridge in the chamber. Each striker includes its own movable retainer. Each retainer holds its corresponding striker in a cocked position until the retainer is moved and the striker is released.
Slots are provided in the timing drum. These slots are positioned to cooperate with the movable retainers holding the strikers in the cocked position. As a particular slot in the timing drum is moved adjacent to a particular retainer, the retainer moves into the slot and thereby releases the corresponding striker. By varying the starting position of each slot on the drum, a delay between the firing of the individual strikers is obtained. In fact, within the constraints of the total movement of the timing drum, any desired sequence and timing of the multiple charges can be provided.
As an example, the pin is preferably configured to remain in place until the user grasps the ring, twists the ring, and pulls the pin free. The device remains in a “safe” condition as long as lever 16 is pressed against the side of outer body 12. The lever is spring-biased away from the body. When the user throws the device, lever 16 pivots out and away from the body. This action initiates the firing sequence.
When the inventive grenade fires, a series of timed detonations blast sound out blast ports 26. Light flashes may also be produced. The device produces multiple reports—such as eight reports. The reports may be configured to occur in a defined time sequence, such as: blast-blast-pause-blast-blast-blast-pause-blast-blast-long pause-blast. The prolonged sequence enhances the confusion caused by the inventive diversionary device.
The inventive mechanisms used to carry out the timed detonations may be realized in a wide variety of ways.
Lever 16 includes paddle 42 and tang 36 with hook 38 on its distal end. Tang 36 slides into slot 44 on lever retainer cap 24, with hook 38 hooking under bridge 46. Through-bore 40 in tang 36 aligns with pin receiver 22. The pin (not shown) is inserted through the aligned through-bore 40 and pin receiver 22.
Base 14 includes multiple firing chambers 28. In the example depicted, eight firing chambers are included in an equally-spaced radial array (centered on the central axis of the base). Spring well 32 is also included in base 14. Core 32 includes a corresponding radial array of striker bores 34. Each striker bore 34 contains a striker configured to detonate a cartridge placed in one of the firing chambers 28. Each striker bore is aligned with a firing chamber. Core 32 also contains delay chamber 82, which houses the timing mechanism for providing the timed detonation sequence. Transverse holes 60, 62 are provided through core 32 in a direction that is normal to its central axis.
Core 32 and base 14 may be made of aluminum. Those skilled in the art will quickly realize that the shapes shown for the base and the core in this particular example lend themselves to machining. The outside diameters can be turned on a lathe. Spring well 30 and delay chamber 82 can be bored or drilled. Firing chambers 28 and striker bores 34 can be drilled. Transverse holes 60, 62 and blast ports 26 can be drilled well. Other manufacturing techniques may be used as well, such as casting.
Outer body 12 slides over the reduced-diameter portion of base 14 as shown. Engagement feature 68 is provided to connect the base and the outer body. The engagement feature could be a snap fit, a thread, or any other suitable connecting feature. It may provide a reversible or permanent connection.
Core 32 fits within outer body 12 and rests against base 14. The lower portion of the core actually captures the cartridges 64 in the firing chambers so that they are in position and ready to fire. The core captures other significant components as well. The lower portion of the core opens into timing drum chamber 100. Timing drum 72 slides into this chamber. In this embodiment, the timing drum is cylindrical. It slides within the cylindrical timing drum chamber. It is urged upward by timing spring 33, which rests within spring well 30 in the base.
The upper portion of the core opens into delay chamber 82. Delay chamber 82 is separated from timing drum chamber 100 by bulkhead 98. Rod 76 passes through the bulkhead and its lower portion connects to timing drum 72. The connection between the rod and the timing drum can be made by a thread, a press fit, an adhesive joint, or other type of connection. The result is that rod 76 moves in unison with the timing drum.
Piston 80 is connected to rod 76 and may in fact be made as in integral part of the rod. The piston moves within delay chamber 82. The delay chamber is filled with a fluid of suitable viscosity (a “delay fluid”). The fluid may be a gas or it may be a liquid. Piston 80 may also contain one or more metering orifices allowing the delay fluid to pass through the piston. Alternatively, a small clearance may be provided between the piston's outer perimeter and the wall of the delay chamber.
The upper portion of the delay chamber is sealed by delay chamber cap 84. The delay chamber cap also mounts an O-ring 86 to prevent leakage around the upper portion of rod 76. Likewise, bulkhead 98 mounts an O-ring 78 to prevent leakage around the rod's lower portion. The O-rings assure that delay fluid does not escape the delay chamber and that the piston must therefore move through the delay fluid without forcing the fluid out of the delay chamber.
As shown in
Lever retainer cap 24 rests over the top of delay chamber cap 84 and core 32. The lever retainer cap is connected to the upper portion of outer body 12 via engagement feature 48. As for the connection between the outer body and the base, the connection at 48 may be a snap, a thread, or any other suitable connection. Whatever form it takes, this connection affixes lever retainer cap 24 to the top of the device.
The reader should recall that timing drum 72 moves in unison with the rod and piston. Thus, when the pin is pulled and the lever is released, the timing drum moves up with the rod. The timing drum is central to the firing mechanism for the inventive device, which will now be described.
Directly above each firing chamber 28 lies a striker 50 (sliding within a striker bore 34 in core 32). A striker spring 52 urges each striker downward toward its corresponding firing chamber. Each striker 50 includes a nose 56, which is shaped to detonate a cartridge. Proximate the nose is shoulder 54. In this version each striker is a radially symmetric shape such as might be turned on a lathe.
But, as timing drum 72 moves upward (once the pin and lever are released), ball hearing retainer 58 will drop into an aligned slot 74 in the timing drum. The presence of the slot in the timing drum allows the shoulder 54 on the striker to push ball bearing retainer 58 inward toward the central axis of the inventive device until the striker clears the ball bearing retainer and fires downward. Once ball bearing retainer 58 drops into slot 74, striker spring 52 propels striker 50 into cartridge 64. Nose 56 on the striker then detonates the cartridge.
The reader will note that transverse hole 62 exists near the bottom of the striker's travel. This transverse hole acts as a vent. It allows the air resting in front of the striker to exit the striker bore as the striker moves toward the cartridge. In the absence of the vent, the velocity of the striker would be reduced.
In order to understand how this firing mechanism produces a desired and predetermined time delay, some additional details of the timing drum must be explained.
In this embodiment the inventive device has eight firing chambers and eight strikers. Accordingly, the timing drum has eight slots 74 cut into its outward-facing cylindrical surface. Each slot includes two aligned portions—a leader slot 90 and a firing slot 92. The slots may assume many different forms. In the version shown, the slots may be made by using a ball end-mill cutting to a variable depth. For the leader slot, the ball end-mill is run at a shallow depth. For the firing slot, the ball end-mill is run at a deeper depth.
In the starting position shown in
Returning to
In looking at
Returning now to
Returning now to
However, in other cases, it is desirable for the first cartridge to be detonated in a much shorter interval. In a door-breaching scenario, for example, the inventive diversionary device should start detonating as soon as it is thrown through a gap between a door and its frame. Since it is difficult to know the scenario that will be encountered beforehand, it is preferable to provide the inventive device with a switchable delay mechanism. Such a mechanism can be provided in tang 36.
A movable block can be provided in the portion of tang 36 overlying the end of rod 76. if a short delay before the first detonation is desired, this movable block can be switched so that the end of rod 76 travels upward and stops at a point just before the first ball bearing retainer reaches its corresponding tripping shoulder. If, on the other hand, a long delay is desired, the movable block can be moved to push the rod end fully inward as shown in
Many other features may optionally be included to allow the user to alter the timing of the mechanism.
A female hexagonal socket suitable for an Allen key could be substituted for the screwdriver slot. Other embodiments might also include a locking plug that threads into the same hole and secures the adjustment rod in place so that it cannot turn.
A more-sophisticated variable timing embodiment is depicted in
Delay rod top 120 is provided with male interrupted thread 124. The male thread is interrupted by a pair of parallel flats 126 (one on either side of the delay rod top). One way to make the delay rod top is to provide a normal male thread on a cylindrical exterior—then grind or cut the two parallel flats 126. This is by no means the only way to make the part, but it serves to explain the desired geometry.
Slot 122 is provided in the outward-facing surface of delay rod top 120. This allows an external tool to adjust the rotational position of delay rod top 120. A hexagonal recess or other similar recess could alternatively be provided.
If the user wants a shorter delay, he or she rotates delay rod top 120 to the position shown in
The user-selectable positions ultimately control an initial rate of motion of the timing drum. If the interrupted threads are engaged, then the initial motion of the timing drum will be slow until the threads are disengaged and the rate of motion then increases. If the interrupted threads are not engaged, then the initial rate of motion will just be the normal rate for the embodiments in which no additional user-selectable delay device (such as the interrupted thread) is provided.
The same type of interrupted thread arrangement could be used at any convenient location along the length of the rod or the other components attached to the rod. For example, an interrupted thread could be provided in the timing cylinder itself. Numerous other features and combinations could be provided. These include:
(1) Shapes other than a radially-symmetric configuration. The inventive device is not limited to the cylindrical configuration illustrated. Further, the illustrated embodiments use an equal radial spacing for all the firing chambers and this need not be the case;
(2) The retainers used to hold the strikers in the “cocked” position need not be spherical. Spherical “ball bearing” retainers are illustrated. However, many other shapes could be used as well;
(3) The device may be made reloadable and reusable. For example, a cocking lever could be provided to return all the strikers to the cocked position. The base may be made removable so that the spent cartridges can be removed and replaced with fresh ones;
(4) The delayed motion of the timing drum may be produced using a mechanism other than a piston. For example, the rate of motion of the rod might be limited by driving a gear motor that accelerates a flywheel;
(5) The bias provided by the timing spring might be replaced by gas pressure acting on a piston;
(6) The use of the term “drum” for the timing drum should not be construed as limiting this component to cylindrical shapes. As one example, the timing drum could have a rectangular cross-section riding in a broached slot; and
(7) The slots shown in the timing drum are circular in cross section (such as made by a ball cutter). However, they could be vee-grooves or any other suitable shape.
The preceding description contains significant detail regarding the novel aspects of the present invention. It should not be construed, however, as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. Accordingly, the scope of the invention should be determined by reference to the claims ultimately presented rather than the examples given.
Number | Name | Date | Kind |
---|---|---|---|
7963227 | Brunn | Jun 2011 | B1 |
9103638 | Thomas | Aug 2015 | B2 |
9261339 | Mancini | Feb 2016 | B2 |
9989341 | Robbins | Jun 2018 | B2 |
Number | Date | Country |
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WO-2016203200 | Dec 2016 | WO |
WO-2016203214 | Dec 2016 | WO |
Number | Date | Country | |
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20180313640 A1 | Nov 2018 | US |