US3000268A - Toggle lock for breech bolt - Google Patents

Description

Sept. 19, 1961 R. s. ROBINSON 3,000,268

TOGGLE LOCK FOR BREECH BOLT Filed Sept. 12, 1952 3 Sheets-Sheet 1 3mm W P 1961 R. s. ROBINSON 3,000,268

TOGGLE LOCK FOR BREECH BOLT Filed Sept. 12, 1952 3 Sheets-Sheet 2 s z a 7 3 3 )2 W T: T

Ill/I 7) W ATTORNEYS Sept. 19, 1961 R. s. ROBINSON 3,000,268

TOGGLE LOCK FOR BREE-CH BOLT Filed Sept. 12, 1952 3 Sheets-Sheet 3 m; 1 ATTORNEYS 3,000,268 TOGGLE LOCK FOR BREECH BOLT Russell S. Robinson, Short Beach, Conn. (124 Via Yella, Lido Isle, Newport Beach, Calif.) Filed Sept. 12, 1952, Ser. No. 309,193 13 Claims. (Cl. 89-189) This invention pertains to an improved mechanism by which the breech bolt can be actuated and locked in recoil-operated firearms, the objects of the invention being to provide a nearly ideal acceleration of the breech bolt at both ends of its reciprocation, to provide locking or secondary support for a directly locked bolt during the period of the explosion, and to make possible a shortened breech or inboard length.

The mechanism, according to the invention, is of the type in which the breech bolt is interlinked to the barrel and to the gun casing by means of a toggle lever and link system so that as the barrel reciprocates during firing, the breech bolt is constrained to move with respect to the barrel whereby at each station of barrel movement in either direction, the bolt is in a certain position with respect to the barrel. There are known bolt-actuating mechanisms of this type in which the toggle members are disposed, when the bolt is forward, so as to be substantially in line with the barrel axis, the recoil force being transmitted in such cases either via the toggle members to the fulcrum point supported in the barrel extension, or via one of the toggle members to lugs incorporated in the barrel extension. Thus, the members of the boltactuating linkage in such known cases must be of heavy construction, which impairs their application to weapons of high rates of fire and/ or heavy caliber. Furthermore, in such constructions, the length of the breech is ruled largely by the fact that the toggle members fold behind the breech bolt during recoil.

In bolt actuating mechanisms according to the invention the fulcrum point of said toggle members is displaced transversely with respect to the barrel axis and may be located forward of the actuating point of the breech bolt when the latter is in recoil position, thereby considerably reducing the breech length of the firearm. Furthermore the operative end of the toggle lever may be set closer to the barrel axis than the fulcrum point of this lever when in recoil position, thereby reducing the depth of the breech casing, and the breech bolt may be locked directly ot the barrel extension, thereby permitting relatively light construction of the actuating linkage.

Moreover, the location of the fulcrum point of the toggle members and the arrangement of the latter provides that during final movement toward battery position the toggle members lie at a substantial angle with respect to the barrel axis (not in substantial alignment therewith) to apply a final transverse component of movement to the breech bolt assembly which locks it directly to the barrel extension. This enables the construction of a firearm with less breech or inboard length to contain the rearwardly folding toggle members than if they were in substantial alignment with the barrel axis. Also the displacement of the fulcrum of the toggle lever away from the barrel axis enables the toggle members to fold rearwardly, when in recoil, wholly upon one side of the breech bolt thereby reducing the inboard length of the firearm and also preventing the sweeping of the toggle link into the space required for the feed mechanism, if a belt feed or other feed means is applied to the top side of the firearm.

One example according to the invention and two alternative locking systems applicable to it are described by reference to the following drawings:

FIG. 1 shows a vertical section passing through the nited States Patent amass Patented Sept. 19, 1961 the rising heel type, the barrel being shown in recoiled' position;

FIG. 2 shows a similar section in which the barrel is in run-out (battery) position with the bolt forward and fully locked;

FIG. 3 is a similar sectional view showing the barrel in an intermediate position;

FIG. 4 is a sectional view on line 44 of FIG. 1;

FIG. 5 is a sectional view on line 5-5 of FIG. 1;

FIG. 6 is a view similar to FIG. 1 showing a modified form of my invention;

FIG. 7 is a sectional view on line 7-7 of FIG. 6;

FIG. 8 is a sectional view on line 8-8 of FIG. 6; and

FIG. 9 is a transverse sectional view showing a further modification.

Referring to FIG. 1, the firearm comprises a gun casing 1, a barrel assembly comprising a barrel 2 and a barrel extension 3, which are mutually fixed together by a thread 4. The barrel assembly is free to slide longitudinally in the gun casing through a limited distance, which is definable by its respective positions in FIGS. 1 and 2, the barrel 2 and a lug 5 on the bar-rel extension 3 sliding respectively in a ring guide 6 and a guide groove 7 constructed within the gun casing 1. The barrel extension 3 is urged forward by a diagrammatically shown recuperator spring 8 which reacts rearwardly against the gun casing 1, and this extension includes two, spaced, substantially parallel, plates 3* and 3.

Upon the adjacent surfaces of the plates 3 and 3 are oppositely disposed, inwardly facing grooves 9, which are sloped in this construction with respect to the axis of the barrel 2, and which support and guide the breech 1 bolt 10 during its reciprocation in the barrel extension 3. At the forward end of the grooves 9 and let into their upper surfaces are oppositely disposed recesses 11, the rear abutments 12 of which provide locking faces for supporting the locking heel 13 of the breech bolt 10. Under the heel 13 of the bolt 10 are a pair of lugs 14 to which is pivoted the forward end of a toggle link 15 by means of a pin 16. The rear end of the link 15 is pivoted to the outer and forked end of a toggle lever 17 by means of a pin 18. The fulcrum pin 19 of the lever 17 is oscillatably supported in the barrel extension 3 at a substantial distance from the axis of the barrel, the axis of the fulcrum pin 19 being so located in the barrel extension 3 that when the lever 17 and link 15 are in substantial alignment, the locking heel 13 of the breech bolt 10 is fully engaged with the abutments 12. On the opposite end of the toggle lever 17 is a stub lever 20 which is at an angle to the body of the lever 17 and which supports a pin 21, the center line of which, with respect to the fulcrum pin 19 axis, is at a substantial angle with respect to the center line between the axis of pin 18 and the fulcrum pin 19. The stub lever pin is pivoted to one end of an actuator link 22, the opposite end of which is oscillatably pinned by a pin 23 to a pair of lugs 24, which are incorpoarted in the base of the gun casing 1. The position of lugs 24 is such that when the barrel is in full forward position, as shown in FIG. 2, the axis of link 22 is substantially perpendicular to the barrel axis. Furthermore, in that same condition, a line joining the centers of pins 19 and 21 is sloped With respect to the barrel axis so that pin 21 is closer to the barrel axis than the fulcrum pin 19. A stop 25 in the barrel extension 3 engages the lever 17 and prevents it from passing too far beyond dead center when the mechanism is in run-out position, as in FIG. 2.

In order to control the front end of the breech bolt 10 and prevent it from rising partly into the recesses 11 of the barrel extension 3 Whilst moving near its forward limits, an opposite pair of laterally extending guide lugs 26 are provided on the front of the body of the breech bolt which are slidably accommodated in grooves 27 in the plates 3 and 3 which run the length of the bolt guide grooves 9, the under side of grooves 9 and 27 lying in the same plane. By means of this construction, the front end of the bolt 10 is constrained to follow the path of the guides 27 and 9 throughout the full length of its movement, whereas the rear end is enabled to rise to perform locking when the bolt is clear of the upper surface of groove 9 and in alignment with recesses 11.

The functioning of the above mechanism is understood by reference to the casing 1 in FIGS. 1, 2 and 3. As the barrel extension 3 accelerates forward under the influence of the recuperator 8 from the position shown in FIG. 1, the breech bolt 10 is constrained by the members of the linkage 15, 17 and 22 to move forward with considerably greater acceleration until after the barrel extension 3 has traveled more than half the distance between recoil and run out as shown in FIG. 3. During the remainder of the run out of the barrel extension 3, the said linkage then constrains the breech bolt 10 to decelerate, until by the time it has reached its forward limit of movement with respect to the barrel extension 3 as indicated in dotted lines in FIG. 1, its relative velocity with respect to the barrel extension 3 is low. The final forward movement of the barrel extension 3 to the position shown in FIG. 2 results in the raising of the heel 13 of the breech bolt by final action of the said linkage into the locking recess 11. During the recoil movement of the barrel extensions from the position shown in FIG. 2 to that shown in FIG. 1, the same functions occur to all members of the mechanism as above described, but in reverse order.

Owing to the slope of the locking abutment 12, to facilitate the locking of the breech bolt 10, there is a small component of force of the explosion transmitted by the breech bolt It} to the barrel extension 3 via the link 15 and lever 17 and their terminal pins 16 and 18, and the fulcrum pin 19.

The grooves 9 in the barrel extension 3, according to the above example, are shown as sloping with respect to the barrel axis. The grooves 5 according to the invention may alternatively be parallel with respect to the barrel axis without other than dimensional alteration to the construction as above disclosed.

Furthermore, the above construction uses a rising heel type of breech bolt. Other bolt-locking systems may be used within the scope and ambit of the invention such as systems using a breech bolt carrying a separate locking piece, one typical example of which is shown in FIGS. 6 to 8, or systems in which the breech bolt partially rotates to lock, one typical example of which is shown in FIG. 9.

Referring to the type of locking mechanism shown in FIGS. 6 to 8, the breech bolt 40 is somewhat T-shaped in form and is provided with laterally extending guide ribs 41 received in inwardly facing grooves 42 in the barrel extension plates 3 and 3 which are substantially parallel with the barrel axis. A locking piece 43 having laterally extending ribs 44 similar in shape to the ribs 41 of the breech bolt is slidably mounted in vertical guides or grooves 45 of the breech bolt. The ribs 44 of the locking piece 43 slide in the grooves 42 and are constrained by these grooves to the position shown in FIG. 8 throughout the greater part of the travel of the bolt. At the forward end of the grooves 42 recesses 46 are cut into the side plates 3* and 3 which communicate with the grooves or which permit the locking piece 43 to rise a limited distance out of the grooves 42 so that the laterally extending lugs or ribs 44 of the locking piece are engaged in the grooves 46 and the bolt is locked in breech-closing position.

The above bolt and locking mechanism can be directly substituted for that shown in FIGS. 1 to 5, the pin 16 being inserted through lugs 47' at the base of the locking piece to connect the toggle link 15 thereto. The toggle lever 17 and other parts of the mechanism are constructed and arranged as shown in FIGS. 1 to 5.

In the further modified form of my invention shown in FIG. 9, which is a transverse sectional view through the breech portion of the gun similar to FIG. 7 but looking forwardly toward the barrel of the firearm, the breech bolt 50 is provided with laterally extending guide lugs 51 which may also serve in part as locking lugs. One of these lugs is extended through a slot 52 in the plate 3 and provided with a ball 53 on its extended end. The lugs 51 slide in grooves 54 in the plates of the barrel extension and these grooves constrain the bolt against turning except at the forward end of its travel where recesses 55 are provided communicating with the grooves 54 which recesses permit the bolt to rotate slightly so as to be locked against its sliding movement in the barrel extension.

In this form of my invention the toggle link (referred to by the numeral 15 in the previously described construction) is in the form of a crank comprising the members 56, 57 and 58. The member 56 is provided with a socket 59 at its upper end to receive the ball 53 and form a ball and socket connection with the bolt. The member 57 is in the form of a pin joining the members 56 and 58 and extends throu h an opening 60 in the plate 3 so that the member 58 lies between the plates of the barrel extension and may be pivotally connected by the pin 18 to the toggle lever 17. This pin 18 may be of slack fit in the member 58 to permit slight lateral oscillation of the latter.

While I have shown and described some preferred embodiments of my invention, it will be understood that it is not to be limited to all of the details shown, but is capable of modification and variation within the spirit of the invention and within the scope of the claims.

What I claim is: i

1. Operating and locking mechanism for the breech bolt of a firearm having a gun casing, a barrel and a barrel extension longitudinally slidable in the gun casing, and a longitudinally sliding breech bolt carried by said barrel extension and locked to it when in battery position, said mechanism including a toggle link connected to the breech bolt to actuate the same, a toggle lever fulcrumed in the barrel extension and pivotally connected to said link, the lever and link constituting toggle members, and said fulcrum point of the lever in the barrel extension being displaced a substantial distance transversely from the barrel axis with respect to the length of the link and being so located that the toggle members are in substantial alignment when the breech bolt is in battery position and fold rearwardly wholly upon. that side of the barrel axis upon which said fulcrum point is located.

2. A breech bolt operating and locking mechanism for a firearm according to claim 1 in which said toggle lever is provided beyond its fulcrum point with a stub lever at an angle to the toggle lever, and said stub lever is oscillatably connected to the gun casing by an actuator link pivoted to the toggle lever and to the gun casing, and the line joining the pivot points of said last-named link being substantially perpendicular to the barrel axis when the breech bolt is in battery position.

3. A breech bolt operating and locking mechanism for a firearm according to claim 2 in which the pivot point of the stub lever to the link is nearer the axis of the barrel when the bolt is in battery position than the fulcrum point of the toggle lever.

4. A breech bolt operating and lockingmechanism for a firearm according to, claim 1 in whichthe barrel extension is provided with a locking recess and the toggle link moves the bolt into saidrecessnat the forward end of the bolt travel.

5. A breech bolt operating and locking mechanism for a firearm having. a gun. casing, a..barre1t and barrel extension longitudinally slidable in the gun casing, said barrel extension being provided with guide grooves, a breech bolt slidably mounted in said grooves, the grooves being sloped with respect to the barrel axis so that their rear ends are further from the barrel axis than their forward ends, a toggle link pivoted at one end to the breech bolt, a toggle lever pivoted at one of its ends to the other end of the toggle link, and said lever being fulcrumed in the barrel extension at a point transversely displaced from the barrel axis a distance greater than the length of the link and in the same radial direction as the direction of displacement of the guide grooves from the barrel axis, and said fulcrum point being so located that when the breech bolt is in forward position the toggle members are in substantial alignment.

6. A breech bolt operating and locking mechanism for a firearm according to claim 5 in which the toggle lever is provided, beyond its fulcrum point, with a stub lever at an angle to the toggle lever, and said stub lever being movably connected to the gun casing by an actuator link, said link being substantially perpendicular to the barrel axis when the breech bolt is in forward position.

7. A breech bolt operating and locking mechanism for a firearm according to claim 5 in which the connection of said actuating link to the stub lever is nearer to the axis of the barrel when the bolt is in forward position than is the fulcrum point of the toggle lever with the barrel extension.

8. A breech bolt operating and locking mechanism for a firearm according to claim 1 in which a locking member is movably mounted in the breech bolt and in which the forward end of the toggle lever is pivoted to said member.

9. A breech bolt operating and locking mechanism for a firearm according to claim 5 in which a locking member is movably mounted in the breech bolt and in which said member is pivoted to the forward end of the toggle link.

10. Operating and locking mechanism for the breech bolt of a firearm having a gun casing, a barrel and a barrel extension longitudinally slidable in the gun casing, and a longitudinally sliding breech bolt carried by said barrel extension and locked to it when in battery position, said mechanism including a toggle link connected to the breech bolt to actuate the same, a toggle lever fulcrumed in the barrel extension and pivotally connected to said link, the lever and link constituting toggle members, said toggle members being in substantial alignment when the bolt is in battery position, and making an acute angle with the barrel axis in a direction to apply a transverse component of movement to the breech bolt to lock it to the barrel assembly.

11. A breech bolt operating and locking mechanism as in claim 1 wherein the bolt is mounted for rotation relatively to the barrel extension, and the latter is provided with locking recesses adjacent its forward end into which the bolt is moved at the end of its forward movement.

12. A breech bolt operation and locking mechanism as set forth in claim 1 in which the fulcrum point of the lever in the barrel extension is disposed forwardly of the point of connection of the toggle link with the breech bolt when the latter is in recoil position.

13. A breech bolt operating and locking mechanism as in claim 5 in which the fulcrum point of the lever in the barrel extension is disposed forwardly of the pivot point of the toggle link with the breech bolt when the latter is in recoil position.

References Cited in the file of this patent UNITED STATES PATENTS 695,784 Bennett et al. Mar. 18, 1902 749,341 Tobisch Jan. 12, 1904 1,083,872 Berthier Jan. 6, 1914 1,518,498 Furrer Dec. 9, 1924 1,801,071 Browning Apr. 14, 1931 FOREIGN PATENTS 211,229 Germany June 28, 1909 50,429 Austria Oct. 11, 1911

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