US2479419A - Semiautomatic firearm convertible to full automatic - Google Patents

Description

Aug. 16, 1949. H. H. SEFRIED, 11 2,479,419

SEMIAUTOMATIC FIREARM CONVERTIBLE TO FULL AUTOMATIC 5 Sheets-Sheet 1 Filed Aug. 25, 1944 All/ENTOR HARRY HSEFRIEO, 2"?" 1949. H. H. SEFRIED,I[ 2,479,419

SEM-IAUTOMATIC FIREARM CONVERTIBLE TO FULL AUTOMATIC Filed Aug. 25, 194-4 5 Sheets-Sheet 2 mum/70R HARRY H.5EFRIED, 2"

ATTORNE rs Aug. 16, 1949. H. H. SEFRIED,1I 2379,4149

SEMIAUTQMATIC FIREARM CONVERTIBLE TO- FULL AUTOMATIC Filed Aug. 25, 1944 5 Sheets-Sheet 3 Aug. 16, 1949. H. H. :SEFRIEDJI 2,479,419

SEMIAUTOMATIC FIREARM CONVERTIBLE TO FULL- AUTOMATIC Filed Aug. 25, 1944 5 Sheets-Sheet 4 INVENTOR HARRY H 5EFR|ED,

H. H. SEFRIED, ]I

SEMIAUTOMATIC FIREARM CONVERTIBLE TO FULL AUTOMATIC Filed Aug. 25, 1944 5 Sheets-Sheet 5 A T TORNE Y8 llwf/vrok HARRY H SEFRIED, 8"

The said hammer is urged to swing in a clockwise direction by a helical hammer-spring 25 Which partly envelops and thrusts forwardly upon a plunger 26 which latter has its forward end engaged with the hammer 23. The hammer-spring 25 is mainly housed within and thrusts rearwardly upon a spring-housing 2'! having its rear end loosely supported by the trigger-pin IT.

The hammer 23 when released to the action of the hammer-spring 25, is adapted to strike the rear end of a firing-plunger 28 and drive the same forwardly to discharge the firearm, in a manner well known in the art. The said firingplunger extends centrally through a breech-bolt 29, which latter will be more fully hereinafter de-,- scribed.

In addition to its primary cocking-lug 2!, the cocking-arm 22 of the hammer 23 is formed at its lower rear portion with a secondary cockinglug 35 adapted on occasion to be engaged and releasably held by the similarly-sloping under-face of a secondary cocking-lug 3i formed at theupper end of a substantially-T-shaped secondarysear 32 (Fig. 11). The said secondary-sear includes a depending tail 33 and a bifurcated bodyportion 34 straddling the adjacent portion of the trigger it and pivotally connected thereto by means of a sear-pin 35.

The rear face of the spring-housing 21 is concave and bears against the rounded forward end of a detent-nose 36 formed at the forward end of the body-portion 34 of the secondary-sear 32. In this manner, the tension of the hammerspring 25 is applied rearwardly through the spring-housing 21, to yieldingly retain the secondary-sear 32 in the position shown in Figs. 1 and 5 relative to the trigger Hi. This effect is made possible by the loose fit of the extreme rear portion of the spring-housing 21 around the trigger-pin I1.

Rotatably mounted in the side-plates l8 and IQ of the trigger-plate unit l2, in a location rearwardly of and slightly below the trigger-pin I1, is a selector-member generally designated by the reference character 31 and of substantially-L- shaped form, as is especially well shown in Figs. 4 and 9. The said selector-member includes a handle-portion 35 projecting outwardly and then longitudinally in a direction parallel with the stock [3. The said selector-member 31 also includes a relatively-large-diametered bearingportion, 39 which is cylindrically contoured and which bears in the side-plate l9 of the triggerplate unit 12 (Fig. 4). At its end opposite the handle-portion 38, the said selector-member is formed with a relatively-small-diametered bearing-portion 40 arranged coaxially with respect to the bearing-portion 39 and rotatably mounted in the side-plate l8. Intermediate its respective bearing- portions 39 and 40, the selector-member 31 is formed with a cylindrically-contoured eccentric 44 which spans the gap between the laterally-spaced-apart side-plates l8 and I9 of the trigger-plate unit [2.

As will more fully hereinafter appear, the selector-member 31 is designed and adapted to be set in two different positions to respectively set the mechanism to cause the firearm to fire semiautomatically or fully automatically. When the outer end of the handle-portion 38 is turned to point rearwardly (Fig. l), the firearm will function as a semiautomatic weapon, i. e., a selfloading firearm which requires the individual actuation of the trigger l 6 to effect the discharge of each shot. When the selector-member 3.1 is

turned so that the outer end of its handle-portion 38 extends horizontally forwardly, as indicated a by broken lines in Fig. 4, the firearm will function as a full automatic weapon, 1. e., will continue to discharge so long as the trigger it is held retired or until the supply of cartridges is exhausted.

To yieldingly retain the selector-member 37 in either of its two positions above referred to, the laterally-extending part of the handle-portion 38 thereof is provided with two detentrecesses 42 and 43 respectively located diametrically opposite each other. The said detentrecesses are alternately adapted to receive the tapered upper end of an inverted cup-shaped detent-plunger '44 mounted for vertical movement in an upwardly-opening recess 45 (Fig. 8) formed in a lug 45 rigid with and laterally offsetting from the trigger-plate unit E2. The said detent-plunger is yieldingly urged upwardly by a helical detent-spring 4'l resting upon the bottom of the recess 45 and thrusting upwardly against the under side of the detent-plunger 44.

Encircling the eccentric 41 of the selectormember 31 is the hub-portion 48 of a sear-actuating lever generally designated by the reference character 49. The said sear-actuating lever also includes a substantially-vertical arm 50 which is slightly curved in a longitudinal direction, as shown. Also as shown, the hub 48 is narrower (Fig. 10) than the width of the arm 55 in a direction transverse to the firearm-structure, and at its junction-point with the said arm provides a shoulder 51' against which thrusts the central transverse reach 52 (Figs. 5, 6 and 8) of a spring 53. The said spring 53 has coiled-portions respectively located on opposite sides of the hubportion 48 of the sear-actuating lever 49, and encircling the adjacent portions of the eccentric M. The said spring 53 is also formed with two forwardly-extending arms 54-54 resting upon the adjacent upper surface of the trigger-plate unit i2 intermediate the side-plates l8 and 19 thereof, so as to cause the said spring 53 to exert a constant-but-yielding eilort to swing the searactuating lever 49 in a counterclockwise direction as viewed in Figs. 1, 5 and 6.

Extending around the rear portion Of the searactuating lever 49 is a hook 55 constituting the integral rear portion of a sear-actuating bar generally designated by the reference character 56. Adjacent its forward end, the sear-actuating bar '56 is formed with a vertically-extending lug 51, the rear face of which is adapted to 'be engaged by a forwardly-facing actuating-shoulder 58. The said actuating-shoulder is formed adjacent the rear end of a bolt-operating slide 59 mounted for reciprocation lengthwise of the firearm structure on the right side thereof. The said boltoperating slide corresponds generally to the member in the well-known Garand rifle and is commonly referred to in the nomenclature thereof as the transmitting-bar.

The sear-actuating bar 56 extends longitudinally of the fire-arm-structure in a plane below the path of reciprocating movement of the boltcperating slide 59, and is supported with capacity for reciprocating movement upon two guide-lugs 60 and BI forming features of the receiver I0 and respectively located to the rear and front of a removable box-magazine 52 adapted to hold a supply of cartridges and to feed the same upwardly in a manner well known in the art.

The breech-bolt 29 before referred to is formed adjacent its forward end with two locking-lugs 63 and 64 respectively extending. from thesaid.

smears-r 5t breech b'olt in"- diametricallyaoppositeudirections: as shown in. Fig -2. The said. breech-bolt riskadaptedi to 400th reciprocateand transversely oscillate .within the upper portion of' the receiver 1B, andthe locking l-u'gs -63 and 'B luofrthe said 5 breech-bolt are respectively adapted to be-cscih lated into and out otengagement with forward ly-facing locking- abutments 65 and 65 respectively located in the opposite side walls of the re ceiver 19 adjacent the forward end thereof; 'asis ;1 especially well shown in Fig. 2.

Extending outwardly from: the locking-lug r64 of-the breech-bolt 29 is. an integralact-uating-lug: =5! extending-into a cam-recess B8-formed in-the inner-face of thebolt-operating shrie -59. The=. said-bolt-operatingslide is formed at its-rear end with a laterally proj ecting :finger-piece '69 i by means-00f which'the firearm may be--manual1yoperated.

For-the purpose of limiting the rearward move-- ment of the sear-actuating bar 56, the receiver lfl is formedwith a forwardly-facing stop abut-- ment 19 which is adapted to be engaged by the rear face of the lug 51 of the said bar 56.

The cam-recess E8 in the bolt-operating slide 59 and theactuating-lug fil of the breech-bolt 29, are so shaped as to cooperate in such manner that when the said bolt-operating slide 59 is moved rearwardly fromits normal forward position, the breech-bolt 29 will befirst turned so as to disengage the locking-lugs B3 andt i respectively from the locking-abutments Ei'and '58 of v the receiver !0, whereupon: the breech-bolt will be -moveddirectly rearwardly. The rearward movementof the'breech-bolt in a manner-usual infirearms effects the extraction and ejection-of the just-fired cartridge.-

Upon its forward stroke; the --bolt-operating-- slide 59 will first draw the breech-bolt29'forward-- 1y until the respective rear faces'of the lock-ingit} lugs 63 and 64- are in'registration with the-locking-abutments B5 andfifi whereupon-the breechbolt 29 will be turned to again lock the breech-- bolt in its forward or breech-closing positionall in a manner common in firearms.

Semiautomatic operation When it is desired to have the firearm above described perform as a semiautomaticfirearm, the selector-member 31 will be :turned intothe posi tion in which it is indicatedby full lines-in Figsr: 1,2, 3 and .4,- to thereby causeth'e eoeentric M 'to shiftthe lower portion-10f the sear-actuating-le'ever wrearwardly and thus render thesaidsear actuating lever inoperative.-

For purposes of making :clearthesemia'utomatieoperation 0f the 'fir'earm above:.=de'scribed, letit beassumed that the hammer 23 has its'pri.-- mary-.cocking-.lug..2|.- engaged with the primary cocking-lug 29 of,the.trigger |6,fas isespecially: wellshown in Fig. 1. Let-'it'furtherbe assumed: that the. firearm is loaded;

Now-when the finger-piece l5 oizthe; trigger/+6 1 is pulled rearwardly, .the primary cocking-lug-v20 of the trigger will be. moveddorwardly :out -of n agement with the primary cockingelug zl of. the, hammer 23.1 This last-described-action :wil-l'. permit the hammer toswing in--a clockwise diea. rection under; the urge; .of the hammer-spring..:25'll and thuscause the said hammer :to strike-the rear. 7 end ,of the firingeplungerdfi, andthus drive the. said firing-plunger forwardly to efiect ithe disez charge of the firearm.

Nowvm :;the caseiof a igaseoperated v:fiream'rror) the; Garandstypmithe discharge; ofatherfirearm;

6% will causertha bolt-ioperati-ng slide 59.:tobedriven rearwardly;

The :rearward movement of the molt-operating; slide: 59 35 justz:above'1. reterred :towill, by. :virtue oir'the-coaction between :its cam-erece'sszfi 8;.and thee. actuating-lugv 5 T of the breech-bo1t; 2 9.',-'-first: causei the. saidbreech-bolt to :be oscillated laterally to; 1 unlock the same, as previously -described;iandstozsg subsequently move the said breechaboltirearwardaily rtonreffe'ct :the extraction and ejection of the-r just-efired cartridge;

As .the:breech-bo1t..is :moved rearward-ly as; above describedthe hammer 23 ;will beuswungiin a counterclockwise direction and should thetrig:-:-:- ger. :l E istill be held pulled during: 'such :move ment, the-saidehammer'will be caught and held; insaxaretired -positi0n by" the engagement of its's secondary .cock-ingdug .39i by the secondary cock-a ingelug 3 I .ofthesecondary-sear 32;- As soon;how-- ever,- as. theitriggercis: released, *the hammer will be released-by: the said secondary-sear but will becaught by the interposition ofrtheprimary cocking-lugsm of the; trigger it in the pathfiof movement of..the primary cocking-lug 2| of the: hammer 23.

Upon the completion'of its rearward travel; the breechebolt '29- will be drawn'forwardly byathe return movement of the bolt-operating slide 59;; whichlatter will act-under the urge of any suit able breech-closing springsuch, for instance, as is shown in Garands U. S0 Pat. No. 1,892,141. This .action'will' cause--the: said breech-bolt to" pick up a fresh cartridge from the upper-end of the box-magazine 62: and to insert such fresh cartridge into thewcartridge-chamber' of-the firearm in a manner-wellknown-inthe art. When' in the: forward travel-of the breech-bolt 29,--its lockingelugszfi3 and [it-arebrought into registry with the locking-abutments 65 andGE Of the -re--- ceiver ;I 0,:the breech bolt' will 'be turned laterally and restored to-its fully-locked position;as indi cated in Figs.'1, 2 rand.3,"-preparatory to effecting-:- another discharge. of the firearm.

Fully automwtz'c. operation.

When it -is=;desired ftoprhave ithe :firearm perform r as ,a fully-automatic..weapon; .the selector-' membertlwill be turned bymeans of" its:,hand1e:-. portion--38 so thats thexsai'd handle-portion. cc.- cupies a forwardly-directed position, as indicated byrbroken lines in Fig; 4; This: movement of: the selector-member 3'5. 1 (substantially 189 will cause .theeccentric 4| to 'shift'the lower portion of =the.sear-actuating lever- 49 forwardly into the positionin-which it is shown in Figs. 5 and 6.

Now :letait be. assumed that the finger-piece"! 5 of the trigger 16 has been-drawn rearwardly 'to. effect the initial discharge ofithe firearmand has; been held; in such retired position. Under these conditions, the initial'discharge of the' fire armwill-cause the breech-boIt ZB to move rearwardly and .to rock the hammer 23 in a counterclockwise. direction,- and cause the secondarycocking-lug '30 of the said hammer to be caught by the. secondary cocking-1ug 3! of the sec-' ondarY-sear 32, as isshown in Fig. 55

Now. when the breech-bolt-EQ and the" boltoperating .slidei. 59 again. move .forwardly, the breech-bolt will be brought into -its:' fully-closed and locked position, and the firearm will: be thereby reloaded',.before the actuating-shoulder 58 .of ..the..bo1teoperating slide 59 has-moved intoengagement with the rear face of the lug 51 of thecsear-r actuating bar- 56. The conditions j ust" desozibedzare' illustrated in Fig.5.

When the parts have reached the relative positions in which they are shown in Fig. 5, the boltoperating slide 59 will continue its forward movement until it is in the position shown in Fig. 6. This latter movement will cause the actuating-shoulder 58 to strike the rear face of the lug 'l'of the sear-actuating bar 56, and thus impart a forward movement to the said bar. The described forward movement of the sear-actuating bar 56 will cause the hook 55 of the latter to rock the sear-actuating lever 49 in a clockwise direction against the tension of the spring 53.

When moved as just above described, the searactuating lever 49 will, in turn, engage its forward face with the tail 33 of the secondarysear 32 to rock the said secondary-sear in a counterclockwise direction. The counterclockwise movement of the secondary-sear 32 will disengage its secondary cocking-lug 3! from the path of movement of the secondary cocking-lug of the hammer 23, so that the parts referred to will assume substantially the positions in which they are shown in Fig. 6. Thus, the hammer 23 will be released to effect the discharge of the firearm, following which latter the parts will again assume the positions in which they are shown in Fig. 5 and then (provided the trigger is held pulled) automatically pass through the phase illustrated in Fig. 6- to again effect the discharge of the firearm.

The features 58, 51, 55, and 49 provide a lost-motion connection between the bolt-operating slide 59 and the secondary-sear 32.

Thus, by appropriately spacing the elements, a time-lag may be had with respect to the interval between the full-closing and the locking of the breech-bolt 29 and the discharge of the firearm when the mechanism thereof is set for full automatic operation.

For instance, by varying the length of stroke of the bolt-operating slide from the position in which it has effected the full-locking of the breech-bolt 29 (Fig. 5) and the position in which it has moved the sear-actuating bar 56 forwardly sufficiently to retire the secondary-sear 32 (Fig. 6), the rate of fire of the firearm may be varied over a wide range. Thus, if the actuating-shoulder 58 of the bolt-operating slide 59 is so positioned as to cause the sear-actuating bar 56 to release the secondary-sear 32 substantially at the same instant that the breech-bolt is closed and locked, the rate of fire will be relatively rapid. On the other hand, should the actuating-shoulder 58 be so positioned as to cause the release of the secondary-sear 352 after the bolt-operating slide 59 has moved forwardly materially past the position in which it effects the locking of the breech-bolt 29, then the rate of discharge of the firearm will be relatively slower than that referred to under the first set of conditions.

The invention may be carried out in other specific ways than those herein set forth without departing from the spirit and essential characteristics of the invention, and the present em-- stantially lengthwise of the firearm adjacent to the said receiver and provided with a forwardlyfacing abutment; an actuating-bar also mounted for reciprocation substantially lengthwise of the firearm adjacent the said receiver and provided adjacent its forward end with a rearwardlyabutment engageable by the forwardly-facing abutment of the said bolt-operating slide for being moved thereby, the said actuating-bar being provided adjacent its rear end with a forwardlyfacing abutment; connecting-means operatively interconnecting the said bolt-operating slide and the said breech-bolt; a pivotal firing-member having a primary cocking-abutment and a secondary cocking-abutment; a trigger having a primary cocking-abutment releasably engageable with the primary cocking-abutment of the said firing-member; a secondary sear carried by and pivotally connected to the said trigger and having a secondary cocking-abutment engageable with the secondary cocking-abutment of said firing-member; a selector-member mounted for rotation in the said trigger-plate unit about an axis which extends substantially transversely of the said unitand at a location beneath the said secondary sear and the forwardly-facing abutment of the said actuating-bar, the said selectormember having an eccentric portion and also having a manually-operable portion projecting from the said trigger-plate unit into position to be manually operated from the exterior of. the firearm; a pivotal sear-actuating member mounted upon the eccentric portion of the said selectormember and extending vertically therefrom past the said secondary scar and upwardly into position to be engaged by the forwardly-facing abutment of the said actuating-bar, the said searactuating member also having a portion intermediate its respective opposite ends which is engagcable with the said secondary sear to release the same; and spring-means urging the upper portion of the said sear-actuating member rearwardly; the said selector-member being constructed and arranged to shift the lower portion of the said sear-actuating member forwardly and backwardly with respect to the said secondary sear into and out of position for effecting the release of the latter.

2. A self-loading firearm, including in combination: a receiver; a trigger-plate unit secured to the lower portion of the said receiver; a breech-bolt movable in the said receiver; a boltoperating slide mounted for reciprocation substantially lengthwise of the firearm adjacent the said receiver and provided with a forwardlyfacing abutment; an actuating-bar also mounted for reciprocation substantially lengthwise of the firearm adjacent the said receiver and provided adjacent its forward end with a rearwardlyfacing abutment engageable by the forwardlyfaoin abutment of the said bolt-operating slide for being moved thereby, the said actuating-bar also being provided adjacent its rear end with a forwardly-facing abutment; connecting-means operatively interconnecting the said bolt-operating slide and the said breech-bolt; a hammer pivotally mounted in the said trigger-plate unit and having a primary cocking-abutment at its front and a, secondary cocking-abutment at its rear; a trigger pivoted to the said trigger-plate unit and having a primary cocking-abutment releasably engageable with the primary cockingabutment at the front of the said firing-member; a secondary sear carried by and pivotally connected to and projecting rearwardly from the said trigger and having a secondary cockingabutment engageable with the rear secondary cocking-abutment of the said firing-member; a selector-member mounted for rotation in the said trigger-plate unit about an axis which extends substantially transversely of the said unit and at a location beneath the said secondary sear and the forwardly-facing abutment of the said actuating-bar, the said selector-member having an eccentric portion and also having a manuallyoperable portion projecting from the said triggerplate unit into position to be manually operated from the exterior of the firearm; a pivotal searactuating member mounted upon the eccentric portion of the said selector-member and extendin vertically therefrom past the said secondary sear and upwardly into position to be engaged by the forwardly-facing abutment of the said actuating-bar, the said sear-actuating member also having a portion intermediate its respective opposite ends which is engageable with the said secondary sear to release the same; and springmeans urging the upper portion of the said searactuating member rearwardly; the said selectormember being constructed and arranged to shift the lower portion of the said sear-actuating member forwardly and backwardly with respect to the said secondary sear into and out of position for effecting the release of the latter.

HARRY H. SEFRIED, II.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 933,254 Knous Sept. 7, 1909 1,103,228 Swebilius et a1 July 14, 1914 1,308,016 Clark June 24, 1919 15 1,333,498 Lang Mar. 9, 1920 1,430,662 Lewis Oct. 3, 1922 1,550,757 Swebilius Aug. 25, 1925 1,892,141 Garand Dec. 27, 1932 2,029,839 Sidgley et al Feb. 4, 1936 20 2,215,470 Johnson Sept. 24, 1940 2,356,727 Reising Aug. 22, 1944 2,388,443 Ruger Nov. 6, 1945 FOREIGN PATENTS 25 Number Country Date 104,493 Austria Oct. 25, 1926 306,328 Germany Sept. 21, 1920

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