Patent Publication Number: US-5425300-A

Title: Magazine-type firearm

Description:
FIELD OF THE INVENTION 
     The present invention relates to a firearm. More particularly this invention concerns a firearm which has a removable magazine or clip in which its cartridges are held. 
     BACKGROUND OF THE INVENTION 
     In a firearm of the automatic, semiautomatic or manual-repetition type having a magazine, when the cartridge moves from the magazine to the firing chamber it must execute a sort of jump entailing a change of position and orientation. The first cartridge of the magazine is aligned with an axis which is approximately parallel to the axis of the barrel, but somewhat lower. This allows a casing of a spent cartridge to be extracted from the firing chamber past the fresh cartridges below it in the clip. For this reason in the firearms of the known kind the cartridge following the spent and expelled one is pushed by the breech block or slide against an inclined surface whose purpose is to guide the fresh cartridge laterally to the firing chamber. 
     During this loading the cartridge is in effect almost wholly out of contact with the edges of the magazine and is not yet received and stabilized in the firing chamber. Thus this precariously held cartridge can get misaligned and jam the weapon with serious consequences for the user. 
     OBJECTS OF THE INVENTION 
     It is therefore an object of the present invention to provide an improved magazine-type firearm. 
     Another object is the provision of such an improved magazine-type firearm which overcomes the above-given disadvantages, that is which loads more smoothly than the prior-art systems so as to reduce the possibility of jamming. 
     SUMMARY OF THE INVENTION 
     A firearm has according to the invention a frame, a magazine fitted in the frame and holding a plurality of cartridges including a top cartridge, a slide displaceable longitudinally on the frame above the magazine and its top cartridge along a longitudinal slide axis between a front position and a rear position, and a barrel centered on a barrel axis, displaceable longitudinally on the frame between respective front and rear positions, and having a rear end formed with a rearwardly open cartridge-receiving firing chamber. In accordance with the invention pivot structure engaged between the barrel and the frame pivots the barrel on the frame between a firing position with the barrel axis substantially parallel to the slide axis and with the firing chamber transversely offset above the top cartridge and a loading position with the barrel axis forming an acute angle with the slide axis and with the firing chamber aligned longitudinally with and open downwardly toward the top cartridge. Cam structure between the barrel, frame, and slide pivots the barrel from its firing position to its loading position on displacement of the barrel and slide rearward out of their front positions and returns the barrel to its firing position on displacement of the barrel and slide forward back into their front positions. 
     Thus according to the instant invention the barrel is tipped down after the spent casing is ejected so that it is longitudinally aligned with the top cartridge in the clip. In this position the slide can push it straight into the firing chamber. The chance of the cartridge getting misaligned and jamming the action is virtually eliminated. 
     In accordance with a further feature of the invention the pivot further enables pivoting of the barrel on the frame into an ejecting position with the barrel axis forming an acute angle with the slide axis and with the firing chamber open upwardly away over the slide and away from the cartridge. 
     The barrel and slide are coupled together by formations for joint longitudinal movement and a stop is provided between the frame and the barrel for arresting the barrel in its rear position and for disengaging the formations from each other when the barrel moves back into its rear position so that the slide can continue to move backward to its rear position independently of the barrel. Thus the barrel and slide move back jointly from their front positions but after some travel the barrel is stopped and the slide continues, ejecting the spent cartridge. On the return movement of the slide it pushes the fresh cartridge into the rear end of the barrel, which meanwhile has been releasably arrested in its rear position, and then the barrel and slide together move forward to their front positions. 
     The pivot according to the invention includes a pivot pin journaled on the front end of the barrel or frame and longitudinally slidable in the front end of the frame or barrel, respectively. Normally the pin is on the front end of the barrel which is formed with a transversely throughgoing hole in which the pivot pin is journaled and the front end of the frame has a pair of confronting longitudinal slots in which ends of the pin are longitudinally slidable. The pivot system can also include a cam mounted on the barrel and a tipping element pivotal on the frame and engaged with the barrel and displaceable by the cam between a level position holding the barrel in the firing position and a tipped position holding the barrel in the loading position. This tipping element has a pair of laterally projecting follower pins sequentially engageable with the cam. In addition a spring-loaded ratchet engageable between the tipping element and the frame releasably retains the barrel in its firing and loading positions, and also in its ejecting position if necessary. The ratchet includes notches on the tipping element and a pawl pivotal on the frame and spring biased into engagement with the notches. 
     The slide according to the invention includes a pair of bars having front ends and a bridge interconnecting the front ends of the bars. The firearm further has a recoil spring braced between the bridge and the frame. The barrel itself has a rear end formed with a longitudinally forwardly open notch. The pivot including a pin seated in the frame and fitting in the forwardly open notch in the front position of the barrel. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     The above and other objects, features, and advantages will become more readily apparent from the following description, reference being made to the accompanying drawing in which: 
     FIG. 1 is a vertical section through the frame of a pistol according to the invention; 
     FIG. 2 is a top view of the element for tipping the barrel of the pistol; 
     FIG. 3 is a side view of the element of FIG. 2; 
     FIG. 4 is a partly sectional side view of the barrel stop; 
     FIG. 5 is a top view of the FIG. 4 barrel stop; 
     FIG. 6 is a side view of the pistol&#39;s barrel; 
     FIG. 7 is a side view of the pistol&#39;s slide; 
     FIG. 8 is a side view of the latch pawl of the pistol; 
     FIG. 9 is a front view of the FIG. 8 latch pawl; 
     FIG. 10 is a front view of the barrel pivot element; 
     FIG. 11 is a vertical section through the fully assembled pistol in the loaded and ready-to-fire position; and 
     FIGS. 12, 13, 14, 15, 16, and 17 are sections like FIG. 11 of the pistol as it is fired and in the succeeding positions as it reloads, the position of FIG. 17 corresponding to the position the pistol assumes just before returning to the position of FIG. 11. 
    
    
     SPECIFIC DESCRIPTION 
     As seen in FIGS. 1 through 11 where the parts--e.g. the trigger and hammer--responsible for firing are left out for clarity of view and because they are not relevant to the invention here--a firearm 50 has a frame 1 carrying a barrel 4 and a slide 8. The barrel 4 is mounted by a slide pivot 7 on the frame 1, and an actuator cam 8h (FIG. 7) integral with the slide 8 operates a tipping element 2 for the barrel 4 during gas-powered or manual displacement of this barrel 4 for reloading. This way an axis 4o of the barrel 4 is inclined downward with respect to an axis 8o of the slide 1 as shown for instance in FIG. 15, in order to eliminate the level differences between its firing chamber 4a and a first cartridge 9 of a magazine 11, in order to feed it into the chamber 4a. 
     In addition the pistol 50 is provided with a retaining element or stop 3 for holding the barrel 4 on the frame 1 when it is inclined. More specifically, the frame 1 has a chamber 1a in which the magazine 11 is held, an empty space 1b holding the rear end of the slide 8, and an empty space 1c holding the front end of the barrel 4. The frame 1 also has a forwardly open cutout or slot 1d whose rear end acts as a stop for a bridge 8d of the slide 8. In turn the empty space 1b is traversed by a hole 1f in which a pawl 5 is detained which acts upon notches 2f, 2g, and 2h on a rear extension of the tipping element 2 under the pressure of a spring 51 which is located in seat 1g of the frame 1. The empty space 1c has also a transverse hole 1m through which passes a pin 3c supporting the retaining element 3 that arrests the barrel 4 when it is retracted. A torque spring 3e on the pin 3c urges the head 3b of the element 3 upward. Guide slots 1i on the frame 1 receive the pivot 7 constituted as a small cylinder 7b which engages with small wings or gudgeons 7a in the guides 1i. 
     The tipping element 2 is a latch which supports the rear part of the barrel 4 via a cylindrical part 2a that fits in a pivot hole 1h of the frame 1 and that, in the front position of the barrel 4, fits in a slot 4e of this barrel 4. The tipping element 2 has a flat bar 2b which supports two buttons 2c and 2d that project laterally toward the outside of the weapon, while a small cam-follower cylinder 2e engages in a groove 4d of the barrel 4. 
     The retainer or stop 3 capable of blocking the barrel 4 in a preselected position via its front end 3a is provided with an upwardly directed rounded bump 3b that holds the barrel 4 in a retracted position under the pressure of the torsion spring 3e wound around the pin 3c and lodged in a rearwardly open cutout 3d of the element to define the rear position of the travel path for the barrel 4. 
     The barrel 4 is provided in its upper rear part above the firing chamber 4a with two symmetrically arranged mounting lugs 4b which can fit removably in corresponding seats 8f of the slide 8. The barrel 4 has a lower base 4c having on one side the groove 4d in which engages the small follower cylinder 2e. The base 4c is formed with the forwardly open slot 4e traversed by the cylindrical part 2a of the tipping element 2 during the firing phase and a recess 4f which on the contrary provides support to the cylindrical part 2a when a cartridge is introduced into the chamber 4a. In addition the base 2c has an inclined surface 4g which in the closing phase of the weapon engages with the cylindrical part 2a to tip the barrel 4 downward. 
     The base 4c as visible in FIG. 11 fits in the empty space 1b while a front base 4h fits in the empty space 1c and has a hole 4i which accommodates the pivot or hinge 7 of the barrel 4. Rearward of the hole 4i on the barrel is a round downwardly open recess or seat 4l in which engages the rounded bump or head 3b of the retainer element 3. 
     An inclined camming surface 4m located rearward of the round recess 41 engages the rounded head 3b as the barrel 4 moves back, allowing its rear end to tip down. A rearwardly directed surface 4n can abut flatly against the front 3a and in this way can determine the stopping point for the barrel 4 during its rearward travel, that is its rear end position. The empty space 1b of the rear base 2c is formed with the hole if in which fits a cylindrical body 5b of the pawl 5. This pawl 5 also has an extension 5c which serves for manually operating a tempered pin 5d which engages in the notches 2f, 2g and 2h of the tipping element 2, retaining it in position during the various position changes of the barrel 4. Advantageously the pawl 5 is in turn retained on the frame 1 by the head of a screw 6 threaded into a laterally open bore 5a in this pawl 5. 
     The slide 8 has a body 8a longitudinally forwardly extended by two parallel bars 8b and 8c and, as already mentioned interconnected transversely in front by the bridge 8d which is formed with a longitudinal hole 8e through which passes a guide rod 55 for a recoil spring 56. Each strap 8b and 8c is formed with one of the seats 8f equipped with a rearwardly directed stop surface 8g on whose inside engages the respective mounting lug 4b. 
     The strap 8b on the right side of the tipping element 2 has the actuator cam 8h which as seen in FIG. 7 is formed with inclined camming surfaces 8i and 8m interconnected by a longitudinal surface 81. 
     The above-described semiautomatic short-stroke pistol operates as follows: 
     To start with the various parts are in the position of FIG. 11, ready to fire. The barrel 4 and the slide 8 are positioned fully forward and the barrel 4 is supported at its front end by the small cylinder 7b lodged within the hole 4i and at its rear end by the pin 2a of the tipping element 2 lodged in the forwardly open slot 4e. The mounting lugs 4b fit inside the seats 8f, engaging forward against the surfaces 8g so that the barrel 4 cannot move longitudinally relative to the slide 8. The axis 4o of the barrel 4 is parallel to or coincident with the axis 8o of the slide 8 and the cartridge 9 is firmly pressed by a rear end 8n of the slide 8 against the bottom of the slide 8 into a position which is clearly lower than the axis 4o of the barrel 4. The contact button 2d is at a spacing of a few millimeters behind the inclined surface 8i. The pawl 5 engages the button 5d in the center notch 2g and the flat bar 2b of the element 2 is also horizontal. 
     In the second phase shown in FIG. 12 the pistol has been fired and a slug 57 has left the barrel 4 which itself starts to move longitudinally straight back, supported by the cylindrical element 2a and the small cylinder 7b. The contact button 2d engages the inclined surface 8i of the cam 8h. 
     In the third phase, represented in FIG. 13, the rearward travel continues due to the inertia of the barrel-slide subassembly. The inclined surface 8i pushes the contact button 2d down, thereby tipping down the front end of the bar 2b and tipping up its rear end. The small cylinder 2e lodged in the groove 4d then pushes the barrel 4 up after the cylindrical element 2a has moved forwardly out of the forwardly open elongated slot 4e, overcoming the resistance of the pawl 5 whose pin 5d now moves into the lower notch 2h. This leaves the barrel 4 in a tipped-up ejecting position with its axis 4o inclined upward and back, forming a small acute angle with the slide axis 8o. The barrel 4 stops in its rear end position against the front 3a of the element 3 and the rounded head 3b engages in the round seat 4l to maintain the barrel 4 in this rear end position. The two mounting lugs 4b have meanwhile been pushed up to disengage the stops 8g and the slide 8, now disengaged from the barrel 4 which is stopped, continues its rearward travel due to inertia. 
     In the fourth phase illustrated in FIG. 14 the slide 8 extracts the cartridge casing 10 which subsequently is expelled laterally in the manner well known in the art. All other elements of the system are in exactly the same position as in the preceding phase of FIG. 13. The raising of the rear part of the barrel 4 has allowed the cartridge casing 10 of the spent cartridge to pass over the upper side edges 11a of the magazine 11. The inclined surface 8i is now located in the vicinity of the contact button 2c. Meanwhile the unillustrated follower in the clip 11 pushes the cartridges therein upward so the uppermost cartridge 9 assumes a position with its axis 9a directed somewhat upward. 
     In the fifth phase shown in FIG. 15, the inclined surface 8i has pushed down the rear of the barrel 4 via the element 2 which is maintained in this position as the pawl 5 ratchets the pin 5d into the upper notch 2f. The recess 4f of the base 4c of the barrel 4 in this position is supported on the cylindrical part 2a. The axis 4o of the barrel 4o in this tipped-down position coincides substantially with the axis 9a of the uppermost cartridge 9 and is inclined rearward and down, again forming a small acute angle with the slide axis 8o. The uppermost cartridge 9 is no longer held down by the rear part 8n of the slide 8 but is now only held back by the edges 11a of the magazine 11. 
     Thus according to the invention the level discrepancy between the firing chamber 4a and the first cartridge 9 in the magazine 11 is eliminated and in fact the axis 9a of the top cartridge 9 and the axis 4o of the barrel are coaxial. This largely eliminates the possibility of any type of jamming of the weapon. 
     Subsequently as shown in FIG. 16 the slide 8 is pushed forward by the recoil spring 56 to push the cartridge 9 into the firing chamber 4a as the cam 8h moves forward, it pushes down the follower cylinder 2d and thereby raises the rear end of the element 2 to a momentarily raised position, with the pin 5d in the upper notch 2f, then finally firmly positioning the pin 5d in the middle notch 2g with the axes 4o and 8o aligned. 
     It has been found that in practice the firearm with magazine according to the invention has proven to be especially advantageous due to the substantial alignment of the barrel 4 with the first cartridge 9 of the magazine 11 during the phase of its introduction in the chamber 4a. This is so because it eliminates the level discrepancy existing between the firing chamber and the first cartridge, eliminating this way completely the most frequent inconvenience in this known type of arms which is the jamming of the firearm. 
     Furthermore, in spite of the tilting of the barrel 4, the firearm which is the object of the present invention has also an optimal firing precision because at the moment when it is fired it is supported at both its front and rear ends 4h and 4c on the frame 1. 
     As already mentioned as an example a semiautomatic pistol with short recoil is illustrated, because this type of weapon has the most complex way of functioning, but the proposed solution can be applied to any type of long or short weapon, be it automatic, semiautomatic or with manual repetition, with a tilting or fixed barrel, a machine gun or the like. The invention conceived this way can be subjected to numerous modifications and variations, all being within the scope of the inventive concept. Any such details can be substituted by elements which are technically equivalent. In practice the materials used as well as the dimensions can be selected as desired, according to the requirements and the state of the art.