Patent Publication Number: US-8534181-B2

Title: Self-loading firearm

Description:
RELATED APPLICATION 
     This application is a continuation-in-part of application Ser. No. 11/093,715, filed Mar. 29, 2005 now abandoned, which is hereby incorporated by reference as if fully set forth herein. 
    
    
     BACKGROUND OF THE INVENTION 
     In a recoil operated self-loading firearm the “recoil” motion caused by firing is harnessed to unlock a portion that moves relative to the handgrip (in the case of a hand gun) or buttstock (in the case of a rifle). This relative motion is used to eject the spent cartridge case and to load another cartridge into the firing chamber, from a stock of cartridges held in a magazine. 
     The unlocking of the two portions, however, cannot take place too quickly after firing the cartridge, because immediately after firing the barrel contains highly pressurized gas that would be dangerous if released prematurely. Too overcome this problem many mechanisms have been invented for unlocking the two firearm sections, after a short delay, to permit the bullet to leave the barrel and the barrel to depressurize. 
     Unfortunately, the mechanisms currently employed to use the recoil of the firearm in locked breech pistols all suffer from one or both of two drawbacks. First, for currently available mechanisms, the delay is inversely proportional to the intensity of the ordinance used. Accordingly, the need for a sufficient unlocking delay places an upper limit on ordinance intensity. Second, many unlocking mechanisms rely on a limited movement of the barrel of the firearm. Any structure in which the barrel of the firearm is not fixed to the part that is held by the operator has the potential for degrading shooting accuracy. 
     Also currently available, and employed particularly in self-loading rifles, is a mechanism by which the pressurized gas present in the gun barrel directly after a shot is fired is employed to eject the spent cartridge case and load an unfired cartridge into the firing chamber. Unfortunately, the complexity of this type of mechanism adds to the weight of the firearm and may be subject to jamming due to incompletely burned propellant powder granules that may be present in the system immediately after shooting. Although it appears that one handgun has been designed utilizing this scheme, it is so heavy as to have limited utility. 
     SUMMARY OF THE INVENTION 
     In a first, separate aspect the present invention is a self-loading firearm that includes a unitary portion including a human interface and a barrel defining a longitudinal dimension. A slidable portion is attached to the unitary portion so as to permit the slidable portion to slide in the longitudinal dimension. The slidable portion includes at least a portion of a firing chamber. In addition, a lock is adapted to selectably fix the slidable portion relative to the unitary portion. Also, a recess in the unitary portion and an inertial member permitted to move inside the recess and urged into a first position, the inertial member adapted to translate into a second position, displaced from said first position by at least 0.1 cm, upon firing of the firearm, in which second position the inertial member begins to change the position of the lock, thereby permitting the slidable portion to move relative to the unitary portion. 
     In a second separate aspect, the present invention is a set of firearms of differing calibers. Each of the firearms includes a unitary portion, including a human interface and a barrel and a moveable portion attached to the unitary portion so as to permit the moveable portion to move relative to the unitary portion, the moveable portion including at least a portion of a firing chamber. Each firearm also includes a lock-unlock mechanism for holding the unitary portion and the moveable portion together until after the firearm is fired and an unlocking delay has passed. Each of the lock-unlock mechanisms is of essentially identical design except for being modified to produce a sufficient unlocking delay for the firearm caliber. Moreover, the essentially identical design is capable of being slightly modified to produce an unlocking delay of sufficient length for a firearm of any caliber. 
     In a third separate aspect, the present invention is a self-loading handgun comprising a barrel and a handgrip and in which the barrel is rigidly and permanently attached to the handgrip, so that there is never any relative motion between the barrel and the handgrip. 
     The foregoing and other objectives, features and advantages of the invention will be more readily understood upon consideration of the following detailed description of the preferred embodiment(s), taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side, partial cut-away, view of a firearm constructed according to the present invention, shown in a first, ready state. 
         FIG. 2  is a side, partial cut-away, view of the firearm of  FIG. 1 , in a second state, which occurs shortly after being fired. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S) 
     Referring to  FIG. 1 , a firearm  10  constructed according to the present invention includes a handgrip  12 , a firing chamber  14 , and a barrel  16 . The handgrip  12  and barrel  16  form a portion of a first part  18 , which engages with a second part  20  that is in the form of a slider. Second part  20  includes the breech block face and is generally locked to the first part  18 , but is briefly unlocked and permitted to translate relative to first part  18 , shortly after firearm  10  is fired, as will be described below. 
     To maintain first part  18  and second part  20  in locked relationship, a locking piece  24  is mounted on first part  18  and urged into locking contact with a notch  26  defined in second part  20 , by a spring  28 , mounted in first part  18 . Referring also to  FIG. 2 , when the firearm  10  is fired, an inertial piece  30  that is retained by a recess wall  32 , retains its position as the remainder of firearm  10  is accelerated in a rearward direction. Locking piece  24  and inertial piece  30  are shaped so that as locking piece  24  moves to the rear, it contacts a slope  34  of inertial piece  30 , which acts to rotate piece  24 , thereby moving piece  24  out of engagement with notch  26 . This unlocks first part  18  from the second part  20 , which permits first part  18  and second part  20  to move relative to each other, permitting the spent cartridge case to be ejected and a new cartridge to be placed into the firing chamber  14 , by mechanisms otherwise well known to skilled persons. It takes an operator a time period on the order of a second to bring the backward motion of a firearm (such as firearm  10 ) to a stop. But the release of part  20  from part  18  must be delayed by about 20 milliseconds to permit the bullet to leave the barrel  16 . Consequently, part  20  will slide backward relative to part  18  after being unlocked (at approximately a hundredth of a second after firing), because it is not being decelerated in rearward movement by the shooter&#39;s hand, as is part  18 . 
     Those skilled in the art will appreciate that the design shown and described above yields great flexibility in the design of self-loading firearms. With the previous technology high intensity ordinance would cause the lock mechanism to unlock prematurely. With the design of firearm  10 , however, the distance between the resting position of slope  34  and the position to which slope  34  must move to unlock piece  24  may be increased in order to adjust the period of the required delay, so that there is no escape of hot gasses. Moreover the barrel  16  is permanently and rigidly attached to handgrip  12 , ensuring stability during firing. 
     Because of the design flexibility of a firearm designed according to the present invention, it is possible to design a relatively light weight, high intensity cartridge self-loading hand gun. Although a gas operated gun of this sort has been designed, it is very heavy. For example, with the previously available technology it would appear to be at least very difficult to make a practical and accurate self loading hand gun or pistol  10  having a 11.43 mm (0.45 in) caliber barrel and a mass of less than 0.75 kg. 
     In a preferred embodiment, inertial piece  30  has a mass of 75 grams and is positioned to travel 0.5 cm before slope  34  contacts locking piece  24  to begin the process of unlocking part  20  from part  18 . In an alternative preferred embodiment inertial piece  30  has a mass of 50 grams, and is similarly positioned to travel 0.5 cm, or in another alternative 0.75 cm, before slope  34  contacts locking piece  24 . In a preferred embodiment inertial piece  30  has a mass of greater than 10 grams, and in another preferred embodiment inertial piece  30  has a mass of greater than 20 grams. 
     The terms and expressions that have been employed in the foregoing specification are used as terms of description and not of limitation. There is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described or portions thereof, it being recognized that the scope of the invention is defined and limited only by the claims which follow. 
     In an alternative preferred embodiment firearm  10  takes the form of a rifle. In an additional alternative preferred embodiment, firearm  10  takes the form of a shotgun.