US2364548A - Bolt mechanism for rifles - Google Patents

Description

Dec. 5, 1944. J. D. PEDERSEN BOLT MEHANISM FOR RIFLES 5 Sheets-Sheet l Original Filed July 29, 1939 INVENTOR klamfifaf/Psfw BY @m #m ATTO R N EYS Dec. 5,V 1944.

J. D. PEDERSEN l BOLT MECHANISM FOR RIFLES 5 sheets-sheet 2 Original Filed July 29, 1939 Dec. 5, 1944. D, PEDERSEN 2,364,548

BOLT MECHANISM FOR RIFLES Original Filed July 29, 1939 5 Sheets-Sheet 3 eff 202 @vd/mi2 ATTORNEYS J. D. PEDERSEN BOLT MECHANISM FOR RIFLES Original Filed July 29, 1939 5 Sheets-Sheet 4 2f'. @5425 jp. 26. /40 /44 l @a l /42 /444 INVENTOR nfo/m/ffaf/wfw @vim ATTDRNEYS Dec. 5, 1944. J, D; PEDERSEN 2,364,548

BOLT MECHANISM FOR RIFLES Original Filed July 29, 1939 5 Sheets-Sheet 5 g l 4 i705 0310/ J/ ATTORNEYS the carrier.

Patented Dec. 5, '.1944

BOLT MECHANISM FOR RIFLES John D. Pedersen, Jackson, Wyo. Original application July 29, 1939, Serial No.

Divided and this application March 13, 1943, Serial No. 478,996

2 Claims.

The present invention relates to an improvement in bolt mechanism for rines, and more particularly rifles of the semi-automatic type such l as shown in my copending application Serial No.

287,221, led July 29, 1939, Patent No. 2,330,737, dated September 28, 1943, of which this application is a division.

The bolt mechanism of the present improvement is of the combined rotary and reciprocatory type, being `rotated between locked and unlocked positions and being reciprocated for opening and closing the breech and magazine chamber. is presented herein in two alternate forms, one of which is an assembly of cover, carrier and bolt and the other merely an assembly of cover and bolt, this second form showing a cover which combines its own functions with that of a carrier. Both of these forms present a substantially smooth uninterrupted closure for the breech to prevent the intrusion of dirt.

Referring to the drawings which show said bolt mechanism and its preferred embodiments,

Fig. 1 is a longitudinal section through the receiver and part of the stock and barrel of a rifle showing the bolt mechanismin breech closing position;

Fig. 2 is a similar longitudinal section showing the bolt mechanism in the open and fully retracted position;

Fig. 3 is a top View oi the bolt assembly;

Fig. 4 is a section through the bolt assembly generally on line 4-4 of Fig. 7;

Fig. 5 is a rear end View of the bolt assembly, the bolt being in its unlocked position;

Fig. 6 is a section on line 6 6 of Fig. 4;

Fig. 7 is a front end View of the bolt assembly, the bolt being in its unlocked position;

Fig. 8 is a fragmentary View of the carrier front end, showing in dotted lines the position of the ejector plunger when the bolt is in the unlocked position;

Fig. 9 is a similar fragmentary front View of In this View the ejector plunger (dotted) is in the position for detaching the bolt from the carrier;

Fig. 10 is a fragmentary section on line Ill- I0 of Fig. 7 to give a side View of the bolt stop shoulders;

Fig. 11 is a projected View of the stopping shoulders of Fig. 10 looking in the direction of the dotted projection lines connecting said ngures;

Fig. 12 is a rear end View of the bolt shown in Fig. 10;

Fig. 13 is a fragmentary section through the ItV receiver near its front end, to show thefront end View of the bolt in its locked position;

Fig. 14 is a fragmentary section through the receiver near its front end, to show lthe front end View of the bolt in its unlocked position;

Fig. 15 is a section on line l5--l5 of Fig. l. In this position the bolt is locked;

Fig. 1,;6 is a section on line iB- of Fig. 1. In this position the bolt is locked;

Fig. 17 is a section on line II-I'I of Fig. 2. In this position the bolt is unlocked;

Fig. 18 is a section on line IB-lil of Fig; 2. In this position the bolt is unlocked;

Fig. 19 is a fragmentary unrolled section on line I9-l9 of Fig. 16, showing the ring pin in its forward position;

Fig. 2O is a fragmentary unrolled section on line 20-20 of Fig. 1'8, showing the ring pin in its retracted position;

. Fig. 21 is a fragmentary unrolled section on line 2I-2I of Fig. 13, showing the fully locked position of the bolt;

Fig. 22 is a fragmentary unrolled section similar to Fig. 21, but showing the bolt in nearly its unlocked position;

Fig. 23 is a fragmentary unrolled section on line 23--23 of Fig. 14, showing the fully unlocked position of the bolt;

Fig. 24 is a fragmentary unrolled section on line 2li- 24 of Fig. 13, showing the left lug of the bolt in the locked position;

Fig. 25 is a fragmentary unrolled section simi lar to Fig. 24, but showing the bolt in nearly its unlocked position;

Fig. 26 is a fragmentary unrolled section on line 26--26 of Fig. 14, showing the ybolt fully unlocked;

Fig. 27 is a top View of the assembled bolt and carrier of alternate construction. The bolt is in the unlocked position;

Fig. 28 is a section on line 26-28 of Fig. 3l;

Fig. 29 is a rear View of the assembled bolt, in the unlocked position;

Fig. 30 is a section on line S--SD of Fig. 28;

Fig. 31 is a front View of the assembled bolt;

Fig. 32 is a fragmentary unrolled section on line 32-32 of Fig. 29, :but with boli; locked and firing pin forward;

Fig. 33 is a fragmentary unrolled section on line 32- -32 of Fig. 29, showing the bolt unlocked and the firing pin retracted;

Fig. 34 is a section on 1ine 30-33 of Fig. 28, but

with the bolt turned to its position ready to deguard member. Other details of this mechanism form no part of the subject matter claimed in` this application and are more fully described in my companion application cf which this is a division.

In Fig. 1 the breech action is in closed position,

in Fig. 2 in open position. VThe breech actionv comprises a'reciprocable and rotatable bo-lt |30. which is provided with a pair of oppcsitely located breech locking lugs |40, |4I, Fig. 3, adapted to lock. ahead of the receiver locking shoulders |42,

|43: locked po-sition, While Fig." 14 shows the bolt rotated to its unlocked position and ready to be moved longitudinally in the receiver The left bolt lug |40 is shown in the locked position engaged withr receiver locking shoulder |42 in Fig. 24. Fig. 25 shows the left bolt lug nearly unlocked from the receiver shoulder |42. During this portion of the unlocking movement the bolt has been cammed toward the rear by the loW pitch helix |42@ of the receiver acting o-n the front end helix |44 of the left bolt lug |40. Fig. 26 shows the completely unlocked position of the bolt lug |40 which has been still further cammed toward the rear by the steep pitch helix |45 of the receiver acting on the helixV |46 of the bolt'lug. The two stages of camming tothe rear constitute the primary extraction which, acting through the extractor |41, starts the fired case from th'e chamber |48 of the barrel. This primary extraction movement also serves as an easy transition from vthe rotary to the rectilinear motion of the bolt.

Radially extending from the front of right bolt lug. |4| is the arm |49 which occupies the helical' cam slot |50 in the enlarged'rear end 85a ofthe slide bar 85 which is adapted to move longitudinally on the receiver, Figs. 13 and 14. Fig.`21 shows the arm. |49 held downwardly by the rear helix of the cam slot |50. This is the locked arm and corresponds to the bolt position shownA in Fig. 25.

In the closing cycle of the breech action', when the .cam slot |50 pulls the bolt forward, the squared ledge |53 of the 'cam slot, Fig. 23, moves forward tocontact the squaredback face |54 of the bolt arm |49 and'to thereby pull the bolt for- Ward without imparting a rotative tendency to the bolt. During this forward travel, the bolt is held from rotation by the left bolt lug |4 0"oc cupying the'slot |55' in the receiver as shown4 in, Figs. 26 and 14. l

When the bolt'reaches'nearly` to its forward position,` its left lug helix |46 comesin contact with the helix |45 of the receiver, see Fig.V 26.

This contact -deflects thev left vlugf upward -to the Fig. 13 `is a front view of the bolt in itsr with 'the cartridgeY rim.

4rier'204, Which'is slidable in the receiver position shown in Fig. 25. This portion of the rotation of the bolt moves the bolt arm |'49 downward off contact with the Aledge |53 of the cam slot |50 to the position shown in Fig. 22. The continued forward travel of the slide causes the helix |5| of the cam slot |50 to ride down the bolt.

arm |49 'to the locked position of the bolt as showrr inFig. y21, in respect-ofthe bolt arm |49 and by-Fig; 24 in respect of the leftbolt lug |40.

It should be understood that the right bolt lug Y, 14|, Figs. 3, 13, 14, is freed from or is in engagement with the right receiver locking shoulder |43 sh'own'in Fig. 14, simultaneously with the freeing or engagement of the left bolt lug |40 from or with the left receiver locking shoulder |42.

The -bolt |39 vis rotatably mounted in a bolt car- The extractor |41 is mounted in the bolt in a radially directed T-slot |92, Fig. 3. The T-slot slopes slightly to the rear and the movement of the extractor'is rigidly controlled so that, as it moves outward from the cartridge rimthe extractor claw |04 moves also slightly to the rear: This rear- Wardinclination ofthe extractor path prevents the claw |94 from slipping off-the cartridge rim during extraction. The extractorplunger y urged forward by the extractor springl ISB-tends atl all times, through the cammingfcontactof face |91 of the plunger and surface |98'ofthe extractor, to force gthe kextractor into engagement The ejector |99'isat-al1 times lurgedforward by the ejector spring'200'z The rear'end'of the Yspring 200 'is supported by the plunger 20|. The `front end ofthe plunger furnishesa stop'to limit Vthe rearward movement of 'the ejectorl 99. A retain'- ing pin 2,03'fnecked at its mid-portion servesto retain the plunger-`20| linthe bolt when the lbolt is 'separatedfrom'the carrier 204; see Figs. 1,A 2, and 4.

The-bolts rear end vrl205-is cylindrical for being journaled-in the carrierV 204. Thefboltis re.- tained thereinvby thewtooth ZGSLOftheU-bolt (Fig. 10) engaging-behind allug 201 of `thefcarrierilig. 4) The^forward part offy the lug 201 has` cut therein a segmental recess 208 in which the Vrear 'endofthe f plunger 20| rides V `when the bolt is` rotatedfrorn*its\'loclted` toits unlockedv position.

Fig.`8 shows the plunger 20| (indottedlines) againstaistop'en'd 209 of the recessA 208 thus preventing the-bolt-from rotating'beyond its unlocked position when the bolt `and Vbolt carrier.vv are removed from the receiver. An inclined cut"2 |0 through the-bottom 'of'lug'201,- Figs. 4, Brand 9, allows the introduction'of a pointedI instrument to depressi they plunger 20| againstV`r the tension of its spring 200,'and thuspermitsY-the bolttol be rotated beyondjits' unlocked-=position to its disassembled position, Fig.l 9, wherethe 'tooth 206 on the `bolt 'clearsthelug 201- of theicarrier.` The bolt may now bedrawn forward' out of thecarnen The carriery 204, in which the-bolt |39-y is mounted,l has lonly reciprocatorymotion in the receiver. `A left rib `2|| of the carrieris constantly guidedinthe slot4 |55-'ofv thereceiver, Figs. 1, 2,13,"14,v 17, etc; The slot |55also is the guide for the left bolt lug |40 when the bolt reciprocates its forward position and the rail 2 I0 reciprocates back in receiver groove I55a when the bolt is being opened. The cover 202 therefore, aids in the guiding of the carrier 204 in the receiver.

The cover is assembled onto the carrier prior to the bolt being assembled to the carrier. The cover has endwise movement on the carrier, between the shoulder 2I'I of the carrier and shoulder 2li:l of the bolt, Figs. 1, 2, and 4. This endwise movement is limited by the rear lug 2 I 9 and forward lug 220 of the cover, Fig. 4. When the bolt is back in its open position, the cover is moved to its forward limit on the carrier, Figs. 2, 3, and 4. As the bolt moves forward to its `closed position, Fig. 1, the front left end 22| of the cover stops against the shoulder 222 of the receiver, Fig. 2, the bolt and carrier continuing to move forward to the closed position. The cover is held forward to the stop 222 of the receiver` by the shoulder 2Il of the carrier, Fig. 1. The rear end of the cover thus extends to the rearward `of the carrier and covers the space between the rear end of the carrier and the end 223 of the receiver opening, Fig. 1, when the bolt is closed.

The firing pin 224 is journaled at its rear portion in the carrier 204 and its forward reduced end 226 projects through the bolt face, and fires the cartridge in the chamber when its rear end 225 is struck by the hammer |27, Fig. 1. The rear end 205 of the bolt is slotted crossvvise at 221, Figs. 12, 15, and 17. Into this slot engages a flattened intermediate wing 228 of the firing pin. The firing pin, therefore, while it has end movement independent of the bolt, must rotate with the bolt. The rear end 225 or the firing pin has a lateral lug 229 whose forward face is provided with a helical cam 230, Fig. 4. Fig. 19 shows the position of lug 229 when the firing pin is forwardin the firing position. Fig. 20 sho-ws the position of lug 229 of the firing pin when the bolt is unlocked, the ring pin having been fully retracted by the helical cam 23| of the carrier as it rotated with the bolt to the unlocked position of the latter. The firing pin is assemb'led to the carrier from the rear, the flattened wind portion 228 entering through grooves 232, 233 in the bore of the carrier, Fig. 6.

The bolt is next inserted into the carrier so that the wing portion 228 is picked up by the f cross slot 221 of the bolt. When the bolt is rotated to its unlocked position with respect to the carrier, Fig. 6, the rear shoulders of the wing portion 228 are rotated out of registration with the grooves 232, 233 of the carrier 204 to retain the firing pin in the carrier. The bolt is provided at its forward portion with bolt stop faces 234, 235, Fig. 10, which are adapted to be engaged by a bolt stop as hereinafter described, for holding the bolt open. The front face 234 is shown in end views, Figs. 7, 13, and 14. The rear face 235 is carved into the lower left corner of the bolt directly behind the front face 234 as shown in Figs. 10 and 11.

In Figs. 27 to 37 inclusive, I have shown an alternative form of bolt mechanism which may be used for the breech closure in place of that heretofore described. In this alternate form the bolt carrier is designed to perform both the functions of a carrier and that of the cover of my first described bolt mechanism. Consequently, there are fewer parts in this second form--it will be lighter in weight and its cost of manufacture will be less than that of the first form.

CLI

The bolt 400 carries the same sort of locking lugs |40, |4| and radial arm |49 and will have the same action for opening and closing the breech as that previously described. The extractor, spring and plunger are also the same excepting that the tail of the plunger 40| has been extended and flattened to give it a limited r spring action. This tail 40 IV projects through a bolt hole 402 in position to intercept an inward flange 403 of the carrier 404 when the carrier is in its forward position on the bolt. In this position notch 405 in the carrier flange' 403 (Figs. 28 and 30) is occupied by the -tail 40| of the plunger. The bolt shoulder 406, coacting with the shoulder 401 of the carrier, limits the endwise rear movement of the carrier on the bolt. 'Ihe carrier partlyV surrounds the' bolt and serves as a cover therefor. This carrier-cover member 404 carries two pairs of prongs 408, 409, 4I0, and 4| I, Figs. 30, 34, 35, and 37, which embrace the bolt and secure it to the carrier. When the bolt and attached carrier are removed from the receiver the carrier may be detached from the bolt by moving the bolt back to its limit in the carrier and then rotating the bolt beyond its unlocked position, Fig. 34. The tail 40| of the plunger, acting against the side of the notch 405 of -the carrier, will yieldingly resist this rotation, to prevent accidental detachment. The bolt may now be further rotated and swung downward clear of the carrier around the right hand prongs 408, 4 I0, as a pivot, the slots 4|2 and 4|3 being formed in the surface of the bolt to provide clearances for the carrier prongs 409 and 4II.

The firing pin 4| 4 has an upright lug 4 I 5 whose upper end reciprocates in a slot 4I6 of the carrier to prevent rotation of the firing pin with respect to the carrier. The lug 4I5 has a helix 4II. When the bolt is in its locked position, the ring pin point 4|8 may protrude through the bolt face 4I9. In that position the ring pinlug 4I5 with respect to the rear end 420 of the bolt is shown by Fig. 32. As the bolt is unlocked its helical cam 42|, coacting with the helix 4II of the firing pin,

7 retracts the firing pin so that the lug 4I5 rides on the surface 422 of the bolt, Fig. 33. The firing pin has a lugy 423, which lies ahead of shoulder 424 and in a recess 423 in the bolt, to retain the firing pin in the bolt. When the bolt is detached from the carrier the firing pin may be rotated to free the engagement of the firing pin lug 423 from the bolt shoulder 424 to permit the withdrawal of the firing pin.

The carrier 404 partakes only of sliding movement while the bolt has both a rotation in the carrier and a sliding movement relative thereto. The carrier is formed with the rib 425 on its right side near the rear end, which reciprocates in receiver groove I55a. At the left side of the carrier is the rib 426 which reciprocates in the left receiver groove |55. The receiver grooves are shown in Fig. 17. The rear end of the carrier serves to close the space between the rear end of the bolt and the end 223 of the opening of the receiver, Fig. 1,.

The ejector 421 is mounted in a lengthwise drilled hole 436 of the bolt as shown in Fig. 28. It is assembled through the front end of the bolt, after the ejector spring 428 and the plunger 429 are inserted. In assembled position a truncated cone head 430 of the plunger 429 engages above an inclined shoulder 43| at the tail of the ejector and displaces the rear end of the ejector downward so that a hook 432 thereof will catch against a"squared.up shoulder 433 of yafradially drilled hole M34` infthe bolt, Fig528. When the frontend 435 of the ejector is forced rearward-.- lyfbyaicartridge head, the rear end of the plungier:;429; abuts the bottom 4310i the hole 436and limits :the inward rnovementof` the ejector. In disassembly, a pointed tool is pressed'. through hole-434` against the bottom rear end of thezejecgtorand .forces the 'hook 432 above they squared upshou1derf433, whereby the ejectorl Willdrop outforwardly from the hole 43E-vin the bolt.

I claim:

1`.- The combination with the receiver of a rifle of `albreech closure therefor comprising a bolt, a bolt carrier in which said bolt is rotatably mounted., y.acover telescopically engaged with said bolt carrier and .arranged to rbe in extended relation thereto when thebreech iszclosed and in collapsed bolt-carrier being slidably engaged'inka way of said. receiver at one side thereof by a single lateral rib formed `on said bolt carrier and said cover being slidably` engaged vin a .Way of said rerelationthereto when the breech is open, said l ceiver at Vthezother side;thereof*byfafsngle'lateral rib formed on'sad cover. Y Y Y Y 2. Thecornbinaton with the receiver-of a'riiie of a breech closure therefor, ,comprisingarbolt a bolt carrier Whchalso serves as -a cover, means for mountingI said bolt: carrier in saidreceiver for reciprocable andV non-rotative movement therein,.,means for-mountingsaidsbolt in said bolt carrier so- `that said bolt 4mayhaveboth rotatable and slidable movement-therein, saidbolt and bolt carrier arranged to'be'inextended relation toone another when the bolt'is inbreech closing position and in .collapsed relation vto4 one another when thefboltis in;position'of.- a'full open breech, `the means for mountingsaid bolt in: said-bolt carrier comprising a` cylindrical por-

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