US2550280A

US2550280A - Semiautomatic rifle

Info

Publication number: US2550280A
Application number: US24304A
Authority: US
Inventors: Edgar D Martin; George E Martin
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-04-30
Filing date: 1948-04-30
Publication date: 1951-04-24
Anticipated expiration: 1968-04-24

Description

April 24, 1951 E. D. MARTIN ET AL SEMIAUTOMATIC RIFLE 3 Sheets-Sheet 1 Filed April 30, 1948 JNVENTORS 06341? D; MARTIN 6- BY @50H65 E. MARTIN TTRNEVS PR 24, 195 E. D. MARTIN ET Al. 2,5502@ SEMIAUTOMATIC RIFLE Filed April 30, 1948 3 Sheets-Sheet 2 f7 49 f4 55 l N VEN TORS 1 50a/.w 0. MART/1v @0,965 f. MART/N Anfon/Mns pli 24, 1951 E. D. MARTIN ET AL SEMIAUTQMATIC RIFLE 5 Sheets-Sheet 5 Filed April 50, 1948 Patented Apr. 24, 1951 UNITED STATES SEMIAUTOMATIC RIFLE Edgar D. Martin and George E. Martin, Corning, Ohio Application April 3o, 1948, seri-amp. 24,304

6 Claims. 1

This invention relates to firearms and more particularly to that class of firearms wherein the recoil .force is employed to eject an expended cartridge and to perform additional functions whereby operation of the firearm kis semi-automatic.

A main object of the invention is to provide a novel and improved Yfirearm of the semi-automatic type which is very safe to handle, sturdy in construction, Vand not subject to jamming.

A furtherbbject of the invention is to provide an improved semi-automatic firearm wherein a succession of cartridges may be fired without requiring the retraction of the bolt for each cartride, the bolt being automatically moved rearwardly after the ring of a cartridge by recoil action, the rearm including safety means for preventing accidental firing thereof, and being very reliable in operation.

Further objects and advantages of the invention will become apparent from the following description and claims, and from the accompanying drawings, wherein:

Figure 1 is a longitudinal vertical cross-sectional view taken through the breech portion of a semi-automatic rifle constructed in accordance with the present invention, the rifle being shown in a cocked position.

Figure 2 is a view similar to Figure 1 but showing the rifle parts in firing positions, the locking means for the cartridge clip being shown in a released position.

Figure 3 is a longitudinal horizontal cross-sectional -view ,taken through the breech portion of the rifle of Figure 1.

Figure 4 is a vertical transverse cross-sectional view taken on line 4-4 of Figure 1.

Figure 5 is a vertical transverse cross-sectional view taken on line 5-5 of Figure 1.

Figure 6 is a vertical cross-sectional view taken on line 3 6 of Figure l.

Figure 7 is a vertical cross-sectional View taken on line 1 1 of Figure 1.

Figure 8 is a fragmentary side elevational 'view of the rifle of Figure 1.

Figure 9 ris a transverse cross-sectional detail View taken through the bolt ofthe rifle of Figure 1 on line 3 9 of Figure 10.

Figure 10 is an enlarged perspective detail view of the bolt of the rifle of Figure 1.

Figure 11 is an enlarged fragmentary detail horizontal cross-sectional view taken through the receiver of the r'iiie of Figure 1 adjacent the forward end of the bolt, showing how an expend- 2 ed cartridge is ejected from the rifle by reeoil action.

Referring to the drawings, Il designates the barrel of the rifle, theY rifle -s'toc'k being shown at I2. Designated at I3 is the receiver, the rear end of barrel II being threaded into the forward endvof the receiver. Rigidly secured to and depending from the forward portion of receiver I2 is the magazine housing I4 and likewise rigidly secured to and depending from the rear portion of receiver I2 is the sear and trigger housing I5. The stock I2 is suitably recessed at IB to receive the depending housings I4 and `I5. Housing l5 is formed with a bottom transverse bar element I1. Secured to bar element by a machine screw I8 is the forward end of the trigger guard I9. The rear end of said trigger guard is secured to the underside of stock I2 by a screw 20. The magazine housing I'II is secured t0 stock I2 by suitable `fastening means, not shown.

Pivotally secured on pin 21 in the .forward portion of sear housing I5 is the sear block 22, said block being biased downwardly by a spring 23 acting upwardly on a pin member 24 bearing on the bottom of receiver I3. Designated at 25 is the sear plate, said plate being formed with a slot 26 engaging the transverse pin 21'. Designated at 28 is the sear spring which bears between pin 2I and the sear plate 25, biasing said sear plate rearwardly and upwardly with respect to pin 21.v The top portion 28 of sear plate 215 projects througha slot 30 formed in receiver I3. The top portion 2971s forwardly` and downwardly inclined yand terminates at its forward end in a lugY 3I adapted to overlie the top lofnsear block 22 when the rifle is in a cocked condition, as shown in Figure I. The body portion `of scar plate 25 is received in a vertical slot 32 formed in sear block 22.

The rear portion of sear block 22 is formed with a recess 33 in which is rotatably received the rounded end 34 of trigger arm 35. The trigger is generally designated at 35 and is pivoted to the side walls of housing I5 by a transverse pin 36. Trigger 35' is provided with a depending finger-actuated arm 31. When arm 31 is pulled rearwardly, sear block 22 is rotated downwardly around pin 2| by trigger arm 35. Pin 21 then acts on Sear plate 25 to move the rear end of the top portion 23 of said sear plate downwardly. If thereafter there vis 'no restraint on said rear end of top portion 29, spring 28 moves sea'r plate rearwardly and' also rotates it upwardly with respect to pin 21, whereby lug 3i is moved down- 3 wardly into slot 32 into abutment with the front Wall of said slot, as shown in Figure 2.

Designated at 38 is a safety catch which is rotatably mounted on a pin 39 secured between the side walls of housing I5, the catch having a spring pressed ball 38 mounted in the lower end thereof and which is movable into and out of seating engagementfin a groove 38" formed in the bottom bar element I1 of the housing I5 upon rotation of the catch 38 toward and away from the sear block 22. formed with a notch 40 engageable with the rear end of sear block 22 when said catch is rotated from the full line position of Figure 1 to its dotted line position with the spring pressed ball 38 seating in the groove 38 in the bottom bar element I1 of the housing I5, whereby block 22 is locked against downward rotation around pin 2|. Catch 38 is provided with a laterally offset upwardly extending actuating arm 4I terminating in a knurled finger plate 42 positioned adjacent the rear portion of receiver I3. Block 22 is locked by moving plate 42 forwardly from the position shown in Figure 3.

Designated at 43 is a plug member which is threaded into the rear end of receiver I3. Plug member 43 is formed with an axial forwardly eX- tending reduced sleeve element44 and encircling said sleeve element is a strong coiled spring 45.

Surrounding spring 45 and longitudinally slidable1 in receiver I3 is a generally cylindrical hammer member 48 whose bore is reduced at 41 to define an internal annular'shoulder against which the forward end of spring 45 bears. The outer surface of hammer member 45 is flattened at its bottom forward portion as shown at 48, the shoulder at the rear end of said flattened portion being engageable by the rear end of sear plate top portion '29 to hold hammer member 45 in a cocked position, as shown in Figure l, against the force of spring 45.

Designated at 49 is a bolt member slidably positioned in the forward portion of receiver I3. Bolt member 49 is generally cylindrical in external contour, as shown in Figures 9 and 10, and is formed with an intermediate transverse slot 50. Extending through said slot 58 and projecting throughja'longitudinal slot 5I formed in the side wall of receiver I3 is a finger bar 52 for manually retracting the bolt 49. Bolt 49 is Safety catch 38 is y groove portion 59 when hammer 45 is in the cocked position shown in Figure 1.

Receiver I3 is formed adjacent its forward end with a longitudinal slot 62 in its side wall and with an internal rib S3 opposite slot 52. Rib 63 is formed with a forwardly facing shoulder 64, the shoulder 64 being adapted to engage the rim 65 of a cartridge case 55 when said cartridge case is driven rearwardly by recoil action when the rifle is fired. As shown in Figure 11, the cartridge case 65 is rotated, by impact with shoulder 64, and is kicked out of the receiver I3 through the slot 62. Bolt 49 is formed with a keyway 31 slidably receiving the rib 63. Pivotally secured in the bolt 49 opposite said keyway is a forwardly extending hook member B8 biased counter-clockwise, as viewed in Figure 3, by a spring 69 positioned in a recess provided therefor in bolt 49 and bearing outwardly on the rear portion of hook member 68. The hooked end of member is engaged over the rim 65 of the cartridge case it through slot 62, as illustrated in Figure 11.

Designated at 18 is a cartridge clip which is i received in magazine housing I4 and contains a plurality of vertically stacked cartridges biased upwardly by a follower plate 1I and a follower spring 12'acting between plate 1I and the bottom;

formed with alongitudinal'axial bore 53 at its rear portion in which is slidably positioned a headed pin 54, and encircling the shank of said pin is a spring which extends into sleeve 44r and bears on the end wall of said sleeve at its rear end and on the head of pin 54 at its forward end. Bar 52 is formed with a recess 55 which receives the head of pin 54, thereby locking bar 52 to bolt 49. Spring 55 exerts a forward biasing pressure on said bolt through theV The forward end of the groove in which firing pin 51 is Vsupported on bolt 49 is increased `in depth, as shownat 59. The forward end of firing pin 51 is formed with an enlarged head 6| adapted to engage the shoulder .at the deepened wall of clip 10. formed with an opening 13 and receivable therein is a lug 14 carried by a clip locking member 15. Member 15 is pivoted between the walls of magazine housing I4 at 16 and is biased toward a lock- The rear wall of the clip 10 is'V formed in member 15.

Spring 11 biases mem-4 ber 15 in a counter-clockwise direction, as viewed in Figure 1, whereby lug 14 is normally main The clipy tained in the opening 13 of a clip 18.

may be unlocked by manually rotating member 15 clockwise by means of a depending handle 18'` carried by said member to the position shown in 'i Figure 2. This is done whenever a clip is erilpty and is to be replaced by a new clip.

The forward end portion of bolt 49 is'` formed with a depending longitudinal rib 19 which normally loverlies the top cartridge in clip 10, as When the rifle is shown in Figures 1 and 2. fired, the recoil moves bolt 49Arearwardly to eject the empty cartridge case, as above described and allows spring 12r to move the stacked'cartridges upwardly so that the top cartridgevin the stack moves into the position formerly'o'ccupied by the ejected cartridge case immediately prior to its ejection from receiver I3. When the bolt 49 is returned by spring 55 to the position ofA Figure 1, bolt 49 pushes the top cartridge into firing position in barrel II.

In operating the rifle, the safety catch 38 is rst moved to the released position shown in full line view in Figure 1. Finger bar 52 is then pulled back as far as it will go. the upper rear end of sear plate 25:withthe This interlocks rear shoulder defined by flattened portion48 of hammer member 48, latching the hammer meme ber in cocked position.

As bar member 52 isf.,A

released, spring 55 moves bolt 49 forwardly and .v bolt 49 moves the top cartridgek in clip 18 vinto firing position in barrel I I, as shown in Figure l'. Since the hammer spring 45 is relatively strong as compared to the sear spring 28, the lug 3| is held in overlying relation to the top of Sear'.l

block 22. The rifle may now be red by pulling on trigger arm 31, whereby sear plate 25 is pivascensori. i

oted downwardly as. above l described, releasing the hammer 48 and'causingithe firing pin-51 to detonate--r-the cartridge by the'impact of its head1'.

evemifi trigger :arml .is held 'ini-itsfrearwardly; pulled: 'ipositionl Ascabove described,` the qrecoili. movement .zofirbolt.d9 and. thaempty cartridge,` caseel causes=..said...cartridge caserta; be eicetedr by rearwardsimpactwith..shouldereGL and as..

spring 55 returnsabolt .49. forwardly, a fresh cartridge is moved by said bolt'into firing position in barrelw! t.

again.

The renewed interlock. of sear plate top portion 29 with the hammer 46 returns the forward top lug 3l of the sear plate from the position of Figure 2, to the position of Figure 1 wherein it overlies the top surface of sear block 22.

When the rie is loaded and cocked, if safety catch 38 is in its locked position, shown in dotted view in Figure 1, it is impossible'to fire the rifle accidentally, inasmuch as both ends of the sear plate top portion abut the top surface of sear block 22, and said searblock is locked againstv rotation.

The isolation of hammer spring A5 from the bolt return spring 55 by sleeve member 44 makes jamming of said springs impossible.

While a specific embodiment of a rearm of the semi-automatic type has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. In a firearm of the character described, a receiver, a hammer member slidably mounted in said receiver, means biasing said hammer member forwardly, a forwardly facing shoulder carried on said hammer member, a sear housing secured to and depending from said receiver, a sear block pivotally mounted in said housing for rotation in a longitudinal plane, a trigger pivoted in said housing and interengaged with said searV block, a sear plate slidably and pivotally secured to said sear block, and spring means acting between said sear plate and sear block biasing said sear plate rearwardly and upwardly with respect to said sear block, the rear end of said sear plate being engageable with said shoulder.

2. In a firearm of the character described, a receiver, a hammer member slidably mounted in said receiver, means biasing said hammer member forwardly, a forwardly-facing shoulder carried on said hammer member, a sear block pivotally secured to said receiver, and a sear plate slidably and pivotally secured to said sear block and engageable with said shoulder.

3. In a firearm, a receiver, a hammer disposed within said receiver and slidably supported. in the latter for movement from a cocked position into a firing position, spring means operatively connected to said hammer for biasing the latter into said firing position, a sear block mounted on said receiver for pivotal movement about a transverse axis toward and away from said receiver, a sear plate disposed contiguous to said sear block and The rifle is nowaready to be iii-edf..T

mounted-i onf. the flatter'. fores1idingrmovexnent-. longitudinally f tnereofvand forlpivotal movementv aboutea second*transverse:.axisspaced fromai first transverseiaxis,1saidfseaiimlaite.hailing :iSg-z uppei-end extending-through; said receiver and engageable :with: said hammereina ,:select;p0Sition; of its sliding.and:-rotary movementfforlocking.;V said .hammer .invsaidlcocked .positiomgand trigger f means` operatively connected tofsaidf-lseal :blockl:

for rotating theslatterabout saidfirst:transverse;

axis and foresimultaneously'.efectinff :thefsliding;4

and pivotal movement .of-.ssaid :searplategout 'of said select position:

4. In\aY-firearmg@ar-receiver, a hammer disposed within said receiver and slidablysupported in the latter for movement from a cocked position into a flringzposition, spring means'operativelycon-f4 nected to said hammer for biasingtheilatten-into e said liring position, a sear block mounted on said receiver for pivotal movement about a transverse axis toward and away from said receiver, a sear plate disposed contiguous to said sear block and mounted on the latter for Sliding movement longitudinally thereof and for pivotal movement about a second transverse axis spaced from said rst transverse axis, said sear plate having its upper end extending through said receiver and engageable with said hammer in a select position of its sliding and rotary movement for locking said hammer in said cocked position, trigger means operatively connected to said sear block for rotating the latter about said first transverse axis and for simultaneously elfecting the sliding and pivotal movement of said sear plate out of said select position, and reslient means operatively connected to said sear plate for biasing the latter into said select position.

5. In a firearm, a receiver, a hammer disposed within said receiver and slidably supported in the latter for movement from a cocked position into a firing position, spring means operatively connected to said hammer for biasing the latter into said firing position, a sear block mounted on said receiver for pivotal movement about a transverse axis toward and away from said receiver, a sear plate disposed contiguous to said sear block and mounted on the latter for sliding movement longitudinally thereof and for pivotal movement about a second transverse axis spaced from said first transverse axis, said sear plate having its upper end extending through said receiver and engageable with said hammer in a selectposition of its sliding and rotary movement for looking said hammer in said cocked position, trigger means operatively connected to said sear block for rotating the latter about said first transverse axis and for simultaneously electing the sliding and pivotal movement of said sear plate out of said select position, and resilient means opera-A tively connected to said sear block for biasing the latter away from said receiver.

6. In a firearm, a receiver, a hammer disposed within said receiver and slidably supported in the latter for movement from a cocked position into a firing position, spring means operatively connected to said hammer for biasing the latter into said firing position, a sear block mounted on said receiver for pivotal movement about a transverse axis toward and away from said receiver, a sear plate disposed contiguous to said sear block and mounted on the latter for sliding movement longitudinally thereof and for pivotal movement about a second transverse axis spaced from said first transverse axis, said sear plate having its upper end extending through said receiver and engageable with said hammer in a select position of its sliding and rotary movement for locking said hammer in said cocked position, trigger means operatively connected to said sear block for rotating the latter about said rst transverse axis and for simultaneously effecting the sliding and pivotal movement of said sear plate out of said select position, resilient means operatively connected to said sear plate for biasing the latter into said select position, and another resilient means operatively connected to said sear block for biasing the latter away from said receiver.

EDGAR D. MARTIN. GEORGE E. MARTIN.

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

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