Abstract:
A shroud for covering the hammer of a firearm, requiring no alteration to the firearm, that may be easily removed or fall off when the firearm is used.

Description:
BACKGROUND 
     Compact double-action revolvers are popular choices for self-defense purposes, both for citizen concealed carry and as backup guns for law enforcement. However, the historic revolver design with an exposed hammer with a spur for cocking can be problematic because it has what amounts to a large metal hook that can catch on clothing while the gun is being drawn. Since guns are drawn, almost by definition, in life-threatening circumstances, any delay in the presentation of the weapon could have fatal consequences. In the past, this problem has been solved in 3 ways. “Hammerless” revolvers have the hammer completely enclosed by the frame. “Shrouded” revolvers have a shroud that covers both sides of the hammer, but leaves a small part of the hammer spur available for thumb-cocking. Finally, the hammer spur may be completely removed or “bobbed.” Hammerless and bobbed revolvers may only be fired double-action, which limits accuracy, while shrouded revolvers may be fired single action, but the remaining exposed portion of the spur is still vulnerable to snagging. Furthermore, the shrouds are often considered aesthetically unappealing. 
     In addition, modification of a revolver from a conventional to a bobbed or shrouded style may require permanent alterations to the gun, preferably performed by a gunsmith. This is costly and can hurt resale value. 
     SUMMARY 
     A removable shroud that attaches to the hammer spur of a firearm. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows one embodiment of a removable hammer shroud mounted on a revolver with the hammer in the uncocked position. 
         FIG. 2  shows one embodiment of a removable hammer shroud falling free from the hammer as the revolver is fired by a user with a relatively low grip on the revolver. 
         FIG. 3  shows one embodiment of a removable hammer shroud falling free from the hammer as the revolver is fired by a user with a relatively high grip on the revolver. 
         FIG. 4  is a perspective drawing of one embodiment of a removable hammer shroud showing the front and interior of the shroud. 
     
    
    
     DESCRIPTION 
       FIG. 1  depicts one embodiment of a removable hammer shroud  10  mounted on revolver  14  in order to temporarily shield the spur  12  of a revolver&#39;s  14  hammer. The shroud has a clip portion  18  which attaches to the hammer, preferably at the spur  12 . This clip portion  18  should grip the spur  12  tightly enough to remain in place during holstered carry. In one embodiment, the clip portion comprises a top  17  and a narrow section  19 . The spur  12  fits between the top  17  and the narrow section  19 , and the narrow section  19  has a width in use that is slightly smaller than that of the spur  12 , pinching the spur  12  and pushing it upward into contact with the top  17 . Since the spur  12  is conventionally checkered to make it non-slip, it will tend to “bite” the top  17  and prevent the shroud  10  from sliding backwards. If the shroud  10  is displaced slightly, the elastic nature of the material will tend to push it back into position. In this way the spur  12  is gripped securely and small forces cannot remove it. 
     For further security in retaining the shroud  10 , it should also contact frame  20  of the revolver  14 . In a preferred embodiment, the frame contacting portion  24  is designed to match the contours of the revolver  14  and drape slightly over the sides, as best shown in  FIG. 4 . This helps the shroud  10  to resist sideward forces that might otherwise dislodge it from the revolver  14 . However, it poses no hindrance to backward movement of the shroud  10 , which is important in use as discussed below. The body  22  of the shroud  10  connects the frame contacting portion  24  to the clip portion  18  and provides a smooth surface along the back  26  of the shroud that guides clothing over the spur  12 , preventing snags. 
     In order to grip the spur  12 , the clip portion  18  must have some elasticity. Preferably, the shroud  10  is formed of a single piece of flexible material. Examples include such polymers as nylon, ABS, or alloyed polymers. Particularly preferred is an alloy of acrylic and PVC, such as Kydex®. Metal may also be used, but has a greater tendency to mar surfaces that it contacts. The dimensions of the shroud  10  must be adapted to the particular revolver  14  to which it is attached. 
     Because the purpose of carrying a concealed handgun and drawing it quickly is self-defense, the shroud  10  must not interfere with the operation of the gun. It must therefore be designed to release its grip on the spur  12  easily when the spur  12  moves backward under pressure from the trigger. For this reason, the clip portion  18  must not grip so tightly that it locks the spur  12  in position. The elasticity of the material and the width of the narrow portion  19  must be chosen so as to balance the need to keep the shroud  10  in place with the need to allow movement of the hammer. Through experiment, it has been determined that Kydex® or ABS approximately 1/16″ thick, when vacuum thermoformed over a die having a narrow portion 0.005″-0.010″ inches narrower than the widest point of the spur, provides this balance. In addition, the shroud  10  is preferably hollow, and void  32  provides space for the spur  12  to move freely. 
     When the hammer moves back, the shroud  10  may fall free in two different ways. When a user has a relatively low grip on the revolver as shown in  FIG. 2 , the shroud  10  initially moves directly backwards with the spur  12 . This pushes the frame contacting portion  24  of the shroud  10  off of the revolver. As the hammer tilts further downward, the front  36  of the shroud  10  contacts the revolver and prevents the shroud  10  from rotating with the spur  12 . This action twists the clip  18  off of the spur  12  and permits the shroud to come loose. 
     When a user has a high grip on the revolver, as shown in  FIG. 3 , the shroud  10  cannot move straight back because of the interference of the user&#39;s hand  38 . Instead it pivots backward. This results in a relatively rapid release by the clip  18  from the spur  12 . However, it poses a problem for proper operation of the revolver, because shroud  10  may become trapped between the tip  28  of the spur  12  and the user&#39;s hand  38 . For this reason, a relatively large void  32  and a relatively thin back wall  40 , as best shown in  FIG. 4 , are both important. Experimentation has shown that for a polymer shroud  10 , a back wall  40  thickness of about 0.080″ or less is sufficiently thin to permit operation of the revolver even with a high grip, while sufficient overall strength is available down to as thin as 0.060″. After the first shot, the shroud  10  typically falls away and no longer is a factor. 
     Production of shroud  10  may be accomplished in a number of ways. A polymer shroud may be injection molded. A metal shroud could be formed on a die. The simplest method of forming a useful shroud is thermoforming, in which a sheet of thermoplastic is heated until it is pliable, and then draped over a die corresponding to the desired final shape of the interior of the shroud  10 , and then pushed downward. A variety of means of pressing the material downward are known, including hydraulic pressure and foam rubber. The simplest is the application of a vacuum underneath the shroud, so that ambient air pressure forms the plastic to the die. This is known as vacuum thermoforming and is widely used in the plastics industry. 
     It should be noted that while spurred hammers are most common on revolvers, there are also other guns which may benefit from the snag-preventing properties of the shroud. Some semi-automatic handguns are designed to permit a double-action first shot followed by single-action shots as the recoiling slide cocks the hammer each time. These may also benefit from a shroud  10  to reduce snags. Also, various rifles and shotguns, including lever and pump-action models, have exposed hammers that can catch on clothing, scabbards, or cases, causing difficulty bringing the gun into service and damage to whatever it snags on. These too may benefit from a removable shroud  10 . Therefore, the spirit of the invention is not limited to any particular embodiment, but may take many forms, defined only by the claims which follow.