Abstract:
A hand-throwable grenade including a detonator initiating mechanism, a detonator and a locking key. The detonator initiating mechanism is activatable by an operator before the grenade is thrown. The detonator is associated with the detonator initiating mechanism. The locking key interacts with the detonator initiating mechanism to preclude an arming of the detonator until the locking key is removed from the detonator initiating mechanism. The locking key has at least one notch therein.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This is a non-provisional application based upon U.S. provisional patent application Ser. No. 61/539,331 entitled “HAND GRENADE”, Sep. 26, 2011, which is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to fuzed devices, and, more particularly, fuzed hand grenades. 
     2. Description of the Related Art 
     A hand grenade is a small bomb that can be thrown by hand. There are at least three types of hand grenades—explosive grenades, chemical grenades, and gas grenades. Explosive hand grenades are the most common used in modern warfare, and they detonate after impact or after a predetermined time after the detonator of the hand grenade is armed. Chemical and gas grenades do not explode, rather they burn or release a gas. 
     Typically grenades explode, projecting shrapnel consisting of pieces of the casing, serrated wire, or an incendiary material. Grenades are manufactured having an explosive or chemical filler with an opening for a fuze. Modern hand grenades have a fuze that is lit by an internal device rather than an external flame typically used in older grenades. 
     Hand grenades manufactured for US forces, such as that shown in  FIG. 1 , typically have a safety handle or lever  4  (which is known by some as the spoon, due to its size and shape) and a removable safety pin  1  that prevents the safety lever  4  from being released. Some grenade types, such as the one shown in  FIG. 1 , also have a safety clip  3  to further prevent the handle from inadvertently coming off in transit. 
     To use a grenade of  FIG. 1 , the soldier grips it with the throwing hand, ensuring that his thumb holds the safety lever  4  in place. This is called the death grip, because releasing the lever could make the grenade detonate, killing the thrower. Left-handed soldiers are advised to invert the grenade, so the thumb is still the digit that holds the safety lever. The soldier then grabs the pull ring  1  with the index or middle finger of the other hand and removes it with a pulling and twisting motion. He then throws the grenade towards the target. 
     Once the soldier throws the grenade, safety lever  4  releases, the striker throws safety lever  4  away from the grenade body  5  as it rotates to detonate the primer (not specifically shown). The primer explodes and ignites the fuze (which serves as a delay element). The fuze burns down to the detonator, which explodes the main charge in body  5 . 
     Several problems exist with the prior art hand grenades, among them the difficulty in operating the system with one hand. Another problem is that the pull ring can catch on something and be inadvertently pulled out. Another problem is that it is difficult to reinsert the pin of the pull ring once it is removed. 
     What is needed in the art is an effective device to overcome these problems with the prior art hand grenades. 
     SUMMARY OF THE INVENTION 
     The present invention provides an effective locking mechanism for a hand grenade that is easily removable when removal is intended, yet does not come out inadvertently. 
     The present invention in one form is directed to a hand-throwable grenade including a detonator initiating mechanism, a detonator and a locking key. The detonator initiating mechanism is activatable by an operator before the grenade is thrown. The detonator is associated with the detonator initiating mechanism. The locking key interacts with the detonator initiating mechanism to preclude an arming of the detonator until the locking key is removed from the detonator initiating mechanism. The locking key has at least one notch therein. 
     An advantage of the present invention is that the key is easily removable by the hand that is holding the grenade. 
     Another advantage of the present invention is that the key is positively locked to the safety lever until the safety clip is removed. 
     Yet another advantage of the present invention is that the key can be easily reinserted into the opening in the safety lever and the opening in the detonator to re-safe the grenade. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of embodiments of the invention taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a side view of a prior art hand grenade; 
         FIG. 2  is a partial side view of an embodiment of a hand grenade of the present invention; 
         FIG. 3  is another partial side view of the hand grenade of  FIG. 2  showing the alignment of slots; 
         FIG. 4  is another partial side view of the hand grenade of  FIGS. 2 and 3  with an embodiment of a key of the present invention installed with the safety lever in the position shown in  FIG. 3 ; 
         FIG. 5  is another partial side view of the hand grenade of  FIGS. 2-4  with the key installed with the safety lever in the position shown in  FIG. 2 ; 
         FIG. 6  is a partial perspective view of another side of the hand grenade of  FIGS. 2-5 ; 
         FIG. 7  is another perspective view of the hand grenade of  FIGS. 2-6 ; 
         FIG. 8  is a side view of the hand grenade of  FIGS. 2-7 ; 
         FIG. 9  is another view of the hand grenade of  FIG. 2-8 ; 
         FIG. 10  is a top view of the hand grenade of  FIGS. 2-9 ; 
         FIG. 11  is a partial view of the hand grenade of  FIGS. 2-10 , with the key of the present invention nearly removed; 
         FIG. 12  is a view of the key used in the hand grenade of  FIGS. 2-11 ; and 
         FIG. 13  is a view of another embodiment of a key of the present invention that can be used with the hand grenade of  FIGS. 2-11 . 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein illustrate embodiments of the invention, and such exemplifications are not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings and more particularly to  FIG. 1  there is shown a prior art hand grenade having a pull ring pin  1 , a confidence clip  2 , a safety clip  3 , a safety lever  4  and a grenade body  5 . Confidence clip  2  is provided to hold pull ring pin  1  in place in an attempt to prevent a premature removal of pull ring pin  1 . An operator has to clear pull ring pin  1  from confidence clip  2 , flip safety clip  3  off, remove pull ring pin  1 , let safety lever  4  come off to activate the fuze of the grenade. These operations are typically carried out with two hands. A disadvantage of this configuration is that the ring of pull ring pin  1  can get caught on something inadvertently causing pull ring pin  1  to be removed. 
     Now referring to  FIGS. 2-13  there is illustrated a new fuzed device  10  in the form of a hand grenade  10  including a bomb portion  12 , a fuze assembly  14 , a safety lever  16 , an opening  18 , a safety clip  20 , an opening  22 , a key  24  and an opening  26 . Key  24  includes notches  28  and a clip  30 . As can be seen in  FIG. 2  opening  18  and opening  26  are not fully aligned while opening  22  is visible beside safety lever  16 . Several of the subsequent figures illustrate the insertion of key  24  and safety clip  20 , which is the reverse of what a fuzed device  10  would normally do in the use of fuzed device  10 . 
     Fuze assembly  14  contains a detonator, which for the ease of explanation fuze assembly  14  can be considered a detonator  14  that is activated when safety lever  16  is removed. Safety lever  16  is a detonator initiating mechanism  16  that is prepared for activation by the removal of clip  30  and key  24  as discussed herein. The detonation process initiates when lever  16  is removed, which may be by the operator releasing lever  16 , or as is often the case the separation of lever  16  from the rest of grenade  10  during the throwing process. 
     In  FIG. 3 , safety lever  16  is pressed closer to bomb portion  12  to cause openings  18  and  26  to substantially align. Movement of lever  16  in direction D has allowed openings  18  and  26  to align. This action causes opening  22  to be obscured from view by the position of safety lever  16 . The movement of safety lever  16  and a spring in fuze assembly  14  (not shown) allows this movement to occur. In  FIG. 4 , key  24  has been inserted through openings  18  and  26  and some of the force, which is applied in direction D, has been released from safety lever  16  allowing a view of a part of opening  22 . In  FIG. 5 , safety lever  16  has been released and key  24  is preventing safety lever  16  from leaving fuze assembly  14 . Additionally referring to  FIGS. 12 and 13 , notches  28  can be seen in key  24 , which are what allows opening  18  to once again not align fully with opening  26  as notches  28  allow a portion of safety lever  16  to enter therein to thereby lock key  24  in position and fully exposing opening  22 . Notches  28  allow a portion of lever  16  to enter thereinto so as to preclude the sliding removal of key  24  from openings  18  and  26 . 
     In  FIG. 6 , safety clip  20  has been inserted into opening  22  and is clipped over a portion of the outer surface of safety lever  16 . Safety clip  20  then prevents safety lever  16  from being depressed enough to remove key  24 . This is an interaction that does not exist in the prior art, with safety clip  20  precluding the removal of key  24 . In contrast the prior art hand grenade as illustrated in  FIG. 1 , allowed the pin  1  to be removed with the safety clip installed. In the present invention the coacting of safety clip  20 , safety lever  16  and key  24  require a prescribed sequence of operations to arm fuze assembly  14 . That sequence is the removal of safety clip  20 , the depressing of safety lever  16 , the pressing of clip  30  outwardly, the sliding of key  24  from openings  18  and  26 , and the release of safety lever  16 . 
     In  FIG. 7  there is shown another view of fuzed device  10  illustrating an opposite side of safety lever  16  from that shown in  FIG. 6 .  FIG. 8  is yet another view of fuze device  10 , which clearly shows key  24 , which not only extends through openings  18  and  26 , but also wraps around safety lever  16  having a clip  30  which additionally serves to secure the position of key  24 . It is also contemplated that key  24  may not wrap around safety lever  16 .  FIG. 9  is a top view of fuzed device  10  with key  24  and safety clip  20  in there normal installed positions. 
       FIGS. 10 and 11  illustrates a method of arming fuzed device  10  with safety clip  20  being removed by pushing with a finger or thumb (not shown) in direction S, then as safety lever  16  is grasped and pressure being applied in direction D, key  24  is pressed upward and in direction L over and across safety lever  16 . Once key  24  is removed fuzed device  24  is armed by the releasing of safety lever  16  in a conventional manner. 
       FIGS. 12 and 13  illustrate possible configurations of key  24  each having notches  28  that interact with elements of fuze assembly  14  and/or safety lever  16  to secure key  24  until safety lever  16  is depressed and key  24  is removed. 
     The present invention was conceived whereby a key  24  with positive locking features, aka “PosiKey”, replaces the existing pull ring  1  and split pin in current hand grenade technologies. Advantageously, the present invention negates the need to control the pull force associated with pull ring pin  1  of the prior art. The present invention further exploits the existing components to create an interlocking system allowing existing inventory to be retrofitted with the PosiKey system. In and of itself, the locking aspect of the new system that exploits the current technology fuze body, safety lever, spring-loaded striker and the innovative key negates the need for confidence clip  2  for the pull ring  1  inasmuch as a pull ring  1  does not exist in the present invention. While with the current technology confidence clip  2  acts as an additional component to defeat extraction of the pull ring  1  and the associated split pin from the grenade, the innovative PosiKey system acts singularly to prevent removal of the key in the normally stowed position. The PosiKey system further exploits the use of a safety clip with an added loop  32  to prevent compression of the spring-loaded striker/safety lever  4 ,  16 , i.e., the ready position when gripped by the operator. Loop  32  performs two functions, it provides a stop for holding safety clip  20  in a proper position relative to lever  16  as loop  32  rests against the face of fuze assembly  14 , and loop  32  adds a spring element to clip  20  so that clip  20  pushes against lever  16  toward the body of grenade  10 . Once the grenade with the PosiKey system is gripped and the safety clip  20  is removed, the safety lever  4 ,  16  can be compressed to the ready position and the key  24  easily removed. The PosiKey further incorporates a tab  30  that latches across the width of the safety lever such that no compression is imparted to the spring-loaded striker/lever. This feature is provided to present a final mode of intent to function the grenade once the grenade is gripped, safety clip removed, and lever compressed. With this latching feature, the PosiKey must be extracted with intent, but unlike the current technology that necessitates two hand operation, the key  24  can be extracted either with thumb action of the throwing hand, which is also used to remove the safety clip, or with the hand alternate to the throwing hand, much like the current technology pull ring. Unlike the current technology, the invention provides for multiple opportunities to abort the intended function of the grenade. Most importantly, the key  24  can be re-inserted after removal, and the safety clip re-inserted to completely and readily re-safe the grenade, while the current technology pull ring and pin cannot be readily re-safed due to deformation of the split pin. 
     Primary motivation for the present invention emanated from observed problems for hand grenades from manufacturing production acceptance and inventory testing for low pull pin retention force. Secondary motivation emanated from operators&#39; practice of taping the pull ring current technology in place, causing a more hazardous scenario for the retrograde of grenades back into the supply chain. To mitigate this, grenades are now being produced by the U.S. Government that adds a confidence clip  2  shown in  FIG. 1  to the grenade. The shortcoming with this technology is that the pull ring  1  still exists and can become snagged by external objects, i.e., even in the stowed position, opportunity can arise that causes the pull ring  1  to detach from confidence clip  2  and further cause the pin  1  to extract from the grenade thereby leaving only the easily sprung safety clip  3  to prevent grenade function if the clip has been left in place. Additional shortcoming is that the confidence clip  2  reduces fuze thread engagement into the grenade body. Calculations are that only three-quarters of a thread is engaged when using the confidence clip  2 . 
     All known prior art hand grenades use a pull ring and pin  1  through the safety lever  4  and fuze body with or without a safety clip trapping the lever to the fuze body. The prior art technology uses a safety clip  3  as a secondary safety feature in the event that the pull ring and pin  1  are inadvertently removed. However, common practice through training is to remove this clip prior to pulling the safety pin. Neither the safety clip  3  nor the confidence clip  2  positively prevents the pull pin  1  from being removed in current technology. 
     Aside from the inherent safety advantages of the multiple detent PosiKey of the present invention, the innovation further allows the grenade to be retrofitted and eliminate the confidence clip  2 , thereby reclaiming the advantages of the original mating assembly configuration of the fuze to grenade body with proper compression of the gasket and proper original design engagement of the threads. By eliminating the confidence clip  2 , modes of failure introduced by the confidence clip&#39;s physical characteristics to control removal of the pull pin  1  are also eliminated. By eliminating the pull ring  1  and its intricately formed safety pin, additional failure modes are eliminated, most notably “pull force” that is a recurring barrier to product acceptability in fuze and grenade manufacturing. Pull pin force continues to be a controlled characteristic in spite of the addition of the confidence clip  2 . Instead of adding components to secure the safety pin and complicating the technology, the PosiKey system reduces the number of components and associated failure modes from current technology. 
     The improved safety clip  20  in the PosiKey system truly serves a safety function by preventing the PosiKey from being removed from the fuze/grenade assembly, prior to the removal of safety clip  20 . 
     With the safety lever  16  in the compressed and unlocked position, the PosiKey can be extracted using a thumb action of the throwing hand similar to that used to remove the safety clip  20 , which theoretically allows one hand operation in extreme combat conditions, e.g., non-throwing hand is incapacitated. 
     Unlike the current technology wherein components can result in pin extraction through material deformation, the PosiKey system of interlocking component feature interfaces cannot be extracted. Even if a portion of key  24  were to suffer from a material failure, the portion of the key internal to the grenade would continue to lock the grenade until the lever is compressed. Should such an event occur, the grenade can still be functioned by compressing the safety lever and allowing the locking residual to fall out. If material failure ever occurred with the PosiKey system, the primary failure mode of the locking key would occur external to the grenade and the residual key internal to the grenade would continue to lock the system. 
     Advantageously, existing inventory can be retrofitted with the PosiKey system as proven by the construction of a working model using surplus materiel. 
     The present invention consists of a system of current technology components with the addition of improvement features that accommodate the PosiKey system locking interface. The system has slots or openings  18  and  26  through the safety lever and fuze body. Slots  18  and  26  are directed towards the grenade inward along a line perpendicular to the safety lever pivot point. These slots are aligned when the safety lever  16  is in the fully compressed position as when gripped and squeezed by the operator&#39;s hand. The required compressing force is not altered from that required for the current technology&#39;s baseline. Interfacing key  24  is made from spring steel and is formed according as illustrated in  FIG. 12  or  13  and machined to create multiple standoffs and recesses, cut-outs or notches  28 , which align respectively with the fuze body and safety lever  16  material in the area of their slots. The standoffs and recesses allow the safety lever  16  to close the slots when the compressing force is removed, allowing the current technology spring-loaded striker to move the safety lever  16  and current technology striker into a locked position with key  24 . Key  24  includes aligned portions of material that is not removed and serves as standoffs in the improved fuze body slots and to lock against the inside and outside of the improved safety lever  16  side material. A shoulder is created on key  24  to serve as a positive stop and to properly align the standoffs and recesses with the improved fuze body and safety lever  16  when key  24  is fully inserted. A third recess is also cut in key  24  to correspond with the striker that also creates an interfacing locking function. Once in the locked position, a total of three interfaces prevent key  24  from being removed from the improved fuze/grenade assembly. These multiple recesses are what create multiple opportunities for the operator to reconsider a decision to function the grenade. As can be seen in the figures notches  28  extend from an edge of key  24  in a direction which is generally perpendicular to the direction in which key  24  is removed from the fuzed device. A portion of lever  16  is positioned in notches  28  when key  24  is precluding the arming of the detonation device. 
     The remaining material of key  24  in the area of the recesses/cut-outs prevents the current technology spring-loaded striker and improved safety lever from further movement, having a material cross section with yield strength greater than that of the current technology split pin used for the same purpose. 
     On the operator side of the key&#39;s positive stop shoulder, the protruding flat steel is further formed to create an external tab that wraps back 180 degrees as shown in several of the figures and traverses the width of safety lever  16 , ending in a catch formed from the tab (shown as clip or tab  30 ) that detents on the opposite side of safety lever  16 . This external tab is formed to not compress the improved safety lever when in the locked position. The tab is also sufficiently formed to catch on the opposite side of safety lever  16  when safety lever  16  is in the fully compressed position. The catch serves to retain key  24  when lever  16  is in the compressed and unlocked position wherein slots  18  and  26  in the fuze body and safety lever  16 , and the current technology striker are aligned to otherwise allow the free extraction of key  24 . This catch feature adds a mode of safety for key extraction. The wrap around tab also includes a narrowing of its cross section to reduce bending stress on the shoulder area of key  24  and allows the catch to spring into place around safety lever  16 . 
     Alternately, a key  24  may be formed with recesses to lock on the fuze body. In this manner, the key is shown in  FIG. 13 . However, this alternative reduces the number of locking interfaces by not providing a locking interface with the striker. 
     To prevent safety lever  16  from being inadvertently compressed from its locked position during stowage, i.e., the environment of transported loose cargo storage or temporary handling trays or pouches, a new safety clip hole  22  is created on the insertion side of the improved fuze body that traps the end of the improved safety clip  20  and creates an opposing force as the improved safety clip  20  latches on the opposite side of safety lever  16 . An improved safety clip  20  is created by culminating in a blunt tip that is inserted into the hole. The improved safety clip  20  is formed to conform to the mating side surfaces of the safety lever and create an interference/spring fit around the safety lever  16  sides when inserted into the said safety clip hole  22 . 
     Once the improved safety clip  20  is inserted into hole  22  in the improved fuze body, the edge of the improved safety lever  16  is constrained and lever  16  is prevented from inadvertent compression, thereby preventing key  24  from being removed and ultimately locking the improved fuze/grenade assembly until clip  20  is removed and lever  16  is compressed. 
     Should the PosiKey not become fully extracted from the grenade for any circumstance or reason, such as operator incapacitation, the improved system will relock the grenade upon release of the safety lever  16 . This cannot be accomplished with current technology. 
     With the improved safety lever  16  in the compressed and unlocked position, the PosiKey allows one-handed operation using the thumb catch on the external tab. 
     This invention may be implemented into any hand grenade that uses a spring-loaded striker under a safety lever without requiring radical modification of current technology to implement. Most grenades in the world use a split pin through the fuze and across the striker to impede grenade function. The PosiKey not only impedes grenade function, but also eliminates the characteristic of pull force associated with current technology pull rings and split pins. 
     Advantageously, this PosiKey system can be implemented into new production as well as retrofitted into existing inventory for both grenade assemblies and practice fuze assemblies. 
     While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.