US2780145A

US2780145A - Breech block return means

Info

Publication number: US2780145A
Application number: US345277A
Authority: US
Inventors: Saive Dieudonne Joseph
Original assignee: FN Herstal SA
Current assignee: FN Herstal SA
Priority date: 1952-04-07
Filing date: 1953-03-30
Publication date: 1957-02-05
Anticipated expiration: 1974-02-05
Also published as: BE510503A; DE1029267B; IT500489A; DE1069037B; GB743211A; FR1073266A

Description

Feb. 5, 1957 Filed March 30, 1953 D. J. SAIVE 2,780,145

BREECH BLOCK RETURN MEANS 5 Sheets-Sheet l INVENTOR. D/EUDONNE JOSEPH SA/VE Feb. 5, 1957 D. J. SAIVE BREECH BLOCK REiuRN MEANS 3 Sheets-Sheet 2 Filed March 30, 1953 INVENTOR. D/EUDO/VNE d0 JE'PH 5A IVE Feb. 5, 1957 D. J. SAIVE BREECH BLOCK RETURN MEANS s Sheds-Sheet 3 Filed March 30, 1953 FlGgfiA INVENTOR. V D/EUDONNE JOSEPH SAIVE 7 J M /9 r 775.

BREECH BLOCK RET lVIEANS Dieudonn Joseph Saive, Wandre, Belgium, assignor to Fabrique Nationale dArmes de Guerre, Herstal, Belgium, a Belgian society This invention relates to an automatic'firearm comprising more especially a fixed barrel, a breech case or frame fixed to this barrel and in which a slide is mounted in order to effect therein, in cooperation with a returning device consisting of a helical spring, a longitudinal reciprocating movement during which it drives a movable bolt of which it also ensures the locking and unlocking, and an under-guard which carries a magazine and a trigger mechanism and towhich is fixed a butt, this under-guard being fitted underneath the said breech case.

The object of the invention is to provide an automatic firearm in which the locking and firing elements comprising principally the breech block and the slide, are easily accessible and can easily be withdrawn.

With this object in view, in an automatic firearm according to the invention the under-guard is articulated to the breech case so as to be lowered underneath the latter by a pivoting movement, in order to render possible the immediate disengagement of the slide and of the bolt and of a removable cover of the said breech case.

In one particularly advantageous embodiment, the helical spring constituting the returning means is lodged in the butt in which it is retained by an element carried by the said spring and having a cup-shaped head which when in forward position is adapted to receive the free end of a rod or connecting link of which the other end is articulated to the rear of the abovementioned slide. The articulated end of this red is lodged in the slide in which it is mounted on a pivot, the said end carrying a stud on which a spring acts in order to lower the said rod and thereby automatically to cause the engagement of its free end in the said cup when the underguard is brought back against the breech case.

Further details and features of the invention will appear in the course of the following description, with reference to the accompanying drawings, of one embodiment, chosen by way of example and not of limitation, of an automatic weapon according to the invention.

In these drawings;

Fig. 1 is a general side elevational view of the firearm with the upperguard in upper or closed position,

Fig. 2 is a similar view but showing the under-guard lowered, i

Fig. 3 is a fragmentary longitudinal section of the weapon with the parts thereof in firing position,

Fig. 4 is a fragmentary longitudinal section of the weapon with the slide and bolt drawn back to the'rear,

Fig. 5 shows the details of the pivotal connection be tween the underguard and the breech case,

Fig. 5a shows, in longitudinal section, the pivot members of the joint between the underguard and the breech case, and

Fig. 6 shows the mounting of the cover of the breech case.

In the difierent figures, the same reference numerals indicate elements which are identical or perform identical functions. V

The weapon comprises more especially a fixed barrel 1 tes Patent G and a breech case or frame 2 fixed to this barrel 1. In the breech case 2 a slide 3 is so mounted as to efiect a reciprocatory movement therein. This movement is caused, when the explosion takes place, by the action of the gases on a piston 41 which repels the slide 3 against the action of a returning device consisting of a helical spring 4. In its movement the slide 3 drives a movable breech piece or bolt 5 and effects the locking and unlocking of the same. For this purpose, the movable bolt 5 is encaged in the slide 3. It carries two symmetrical lateral projections 42 associated with a system 43 of corresponding ramps and abutments provided in the slide 3.

The underguard has a forwardly extending portion fitted underneath the rear part of the breech case 2 and an upright abutment 27 having a forward face engageable with the rear open end of the frame for closing the same. A butt or stock 7 is connected to the underguard. The forwardly extending portion of the underguard carries a trigger mechanism and is arranged to receive a magazine such as that designated by the numeral 53 in the drawings. y

In one advantageous embodiment of the invention, the front end of the under-guard 6 is articulated to the breech case by means of a pivot 9. On this pivot is mounted a lever 11 for the control of fire in bursts, which lever cooperates with the magazine and trigger mechanism. The under-guard 6 is retained against the breech case 2 by means of a locking member 12 positioned rearwardly of the pivot 9. The locking member 12 books into a lug 13 provided under the breech case 2. It is also adapted to be manipulated by means of a spring pusher 14 projecting from one of the lateral surfaces of the under-guard 6. The breech case 2 carries the central hinge plate 15 of the pivot 9 while the two side plates 16 of the underguard 6 carry, as extensions thereof, the two extreme hinge plates 17 of this pivot. The lever 11 for the control of fire in bursts is placed between the central hinge plate 15 and one of the abovementioned two extreme hinge plates 17. The pin 10 of the joint 9 is hollow. It carries a knob 18 at one end, while its other end is internally threaded to enable the neck 19 of a stem 20 to be screwed therein. This stem, of which the body 21 is split, is engaged in the hollow pin '10 and passes right through the knob 18 by means of a central hole 22 made through this knob. The penetration of the stem 20 into the hollow pin 10 is limited by a head 23. The head 23 is a knob similar to the knob 18. The two

knobs

18 and 23 thus clamp and mask the extreme hinge plates 17 of the pivot 9. Preferably the head 23 of the stem 20 is provided with a diametral recess 24 shaped for the edgewise engagement therein of a circular object which can be used for easily assembling or dismantling the stem 20 and the hollow pin 10. The circular object in question may simply be a coin.

In one particularly advantageous embodiment, the helical spring 4 constituting the returning device is lodgedin a tube secured to the abutment 27 and extending rearwardly into the butt 7. It is retained therein by an element or plunger 25 which it carries. The said element '25 has a head 26 in the form of a cup which, when the plunger is in the forward position shown in Fig. 3, is adjacent the front face of the abutment 27 to receive the free end 28 of a rod or connecting link 29 articulated at its other end 30 to the rear of the slide 3. The articulated end 30 0f the rod 29 is lodged in the slide, 3. It is mounted therein on a pivot 31 and carries a stud 32 on which a spring 33, sunk into the slide 3, acts in order to lower the rod 23 and thus automatically ensures the engagement of its free end 28 in the cup 26 when the under- 7 guard 6 is brought back against the breech case 2. This engagement is facilitated by a recess 44 made in said front face of the abutment 27. The slide 3 is provided with means for retaining the bolt 5. The slide at its rear end has a depending heel or lug 34 which extends to the bottom of the breech case 2 and which lug is provided with a hole 35 for the passage of the rear projection 36 of a striker enclosed in the bolt 5. As a result, the bolt cannot escape freely from the slide 3, the rear projection 36 of the striker preventing the withdrawal of the lateral projection 42 of the bolt 5. The association of the slide 3 and the bolt 5 effected in this manner facilitates the withdrawal and replacement of these elements while at the same time preventing them from being separated from one another at times when such separation would be undesirable. In order to disengage the bolt 5 from the slide 3 it is necessary to exert pressure on the rear projection 36, against the action of the spring of the striker, in order to get it out of the hole in the lug 34.

As stated, the lever 11 is mounted on the pivot which pivotally connects the breech frame to the underguard. This is of advantage in that, although the lever cooperates on one hand with the slide 3 carried by the breech frame and on the other hand with the hammer of the trigger mechanism carried by the underguard, a very simple and effective arrangement is provided which permits the underguard to be swung to an open position and then returned to closed position. Referring to Figs. 3 and 4 of the drawings, it will be noted that the hammer 51 has a notch 69 with which the forward end of the sear 61 is adapted to cooperate to hold the hammer in cocked position. The sear is carried by a trigger 62. Carried by the breech frame above the tail end of the trigger is a stud 63 having a lever 64 (see Fig. l) for selectively adjusting the stud to three positions, namely, first, a safety position; second, a position which will permit the firing of a single shot only; and third, a position which will permit automatic firing of the gun when the trigger is held in pulled position. The lever 11 has a rearwardly extending tooth 65 adapted to cooperate with a second notch 66 on the hammer. The forward end of the lever has a toe 6'7 adapted to be engaged by a forwardly facing shoulder 63 adjacent the rear end of the slide 3. In Figs. 3 and 4- the stud 63 is shown in the third position in which the gun may be automatically fired. When the breech bolt and slide 3 are moved from theposition shown in Fig. 3 to the retracted position shown in Fig. 4, the hammer is cooked and the lever 11 assumes the position shown in Fig. 4. The slide and breech bolt will now be moved forwardly under the influence of spring 4 and, as the slide S moves to its final forward position, the shouider 68 on the slide will engage the toe 67 of the lever, thus releasing the hammer; and, assuming that the trigger is held in pulled position, the hammer will strike the firing pin. 7 I

The removable cover 8 is an elongated member made of sheet metal. It is channel-shaped and acts resiliently in a transverse direction. For this-purpose it is provided with a longitudinal projection 37 at" its center. It is provided with longitudinal flanges3$ for engaging with hard friction in corresponding longitudinal grooves 39 made in the upper parts of the breech case 2. It is obvious that the front part of the cover 8 will be provided with an opening 45 for the passage of ejected cartridge cases. The weapon is provided with-means for aiming by means of a V-shaped backsight 46 and a foresight 47.

In addition, it will be noted that one of the sides of the breech case 2 carries externally a cocking rod 48'. This rod 48 is adapted to slide in a slide 49 in which it is engaged. Its inner surface carries a stud adapted to move in a groove made at the bottom of the said slide 4 9, this stud passing through the side in question and constituting a forward abutment for the slide 3. The rod 48 is provided on its outer surface with a manipulating knob 50011 which the operator acts in order to draw the

locking elements

3 and 5 to the rear in order to cook the instrument, described. In this position, the

. associated with the bolt 5.

hammer 51 is lowered and permits the disengagement of the slide 3 and of the bolt 5. To effect this latter operation and, if required, the removal of the cover 8, the operator acts on the pusher 14 and lowers the underguard 6 to which the butt 7 is fixed. This movement is limited by the case 52 of the magazine 53 which stops the front bottom edge of the under-guard 6. It is then easily possible to withdraw the cover 8, and the slide 3 The disengagement of the slide 3 and the bolt 5 as a unit is effected very easily by puiling on the red 29. In order to reassemble the weapon, the bolt, slide and cover are replaced and the under-guard 6 is brought back against the breech case 2.

The weapon according to the invention offers the decided advantage that it comprises locking members which are easily accessible and can easily be withdrawn without any risk of the parts becoming separated from one another.

It is to'be understood that the invention is in no way limited to the embodiment hereinbefore described, in which many modifications can be made without departure from the scope of the present patent application.

More particularly, the weapon could be completed by various accessories such asa muzzle gland, a tenon for the attachment of a bayonet, and the like.

I claim:

1. In an automatic firearm in combination, a breech frame open at' its rear end, a slide mounted for longitudinal reciprocating movement in said frame and removable therefroni through the open rear end thereof, a breech bolt in said slide and operated by the movements thereof and removable therewith, an underguard having a forwardly extending portion underlying the rear portion of said frame and an upright abutment having a front face engageable with the rear end of said frame for closing the same, means for pivoting said underguard at its forward end to said frame for swinging movement between a closed positionin which said abutment closes the rear end of said frame and an open position in which said abutment is below the open end of said frame, means for releasably locking said underguard in closed position, returning spring means in the underguard for normally urging said slide to its forward position and comprising a plunger and a spring behind the plunger, said plunger having a recess at its forward end adjacent said face when the plunger is in forward position, a connecting link pivoted to the rear end of saidslide and extending rearwardly thereof, and a spring carried by said slide for urging said link to a downwardly inclined position to cause the rear end of said link to move into said recess during the closing movement of said'underguard, said slide, breech block and connecting link being removable from said frame by withdrawing the same longitudinally and rearwardly from the open end of the frame when the underguard is in open position.

2. In an automatic firearm having a breech frame and underguard having a forwardly extending portion arrrangedto underlie the rear portion of the frame, a pin References Cited in the file of this patent UNITED STATES PATENTS Hepburn Apr. 13, 1909 Holek Sept. 1, 1931 (Other references on following page) 6 Whittemore Oct. 12, 1948 Foster July 5, 1949 Grebey June 2, 1953 FOREIGN PATENTS France Sept. 27, 1943