US2656635A - Cartridge retracting device - Google Patents

Description

Oct. 27, 1953 C. H. STEVENS ETAL 2,656,635

CARTRIDGE RETRACTING DEVICE Filed y 22. 1951 gwuc/wfww Bhnrlea H- El-havens Knrl ALT Purl Er m JM+ 4M3 Patented Oct. 27, 1953 UNITED STATES; PATENT OFFICE GARTRHTGE RETRACTING} Qharles H. Stevens, Springfield, and Karl W; Meier, Feeding Hill's, Mass... assignors. to the United States off'America as represented by the Secretaryofthe Army Application May 2,2;11951,a Selfiak No. 2213584 3I CIaims. (CI. 42-68). CGrantedi under Title 35, U. S. Code (1952),

sec. 266),:

invention described inthe specification and claims may be mamrfa'ctured and used by orfor the Government for governmental purposes without the paymentof' any royal-tythereon.

This invention relates to cartridge case extracting means forfirearms and is more pa-rti'c-- ularly directed tomeans' for automatically loosening fired cartridge cases in their chambers immediatelyprior' to the actual extraction therefrom:

In high speed automatic firearms of the type wherein a plurality of a-nnularly disposed firing chambersare provided a revolving drum, a cartridge is first rammed into the leading one of the-firing chambers and their positioned therein byafixed guideoperative on the base of the cartridge case so that the annular extractor groove therein willbe properly aligned for en gagement by the claw of the extractor; ever, due to manufacturing tolerances, the overalllength of each cartridge case may vary fromone to the othen Thus; some cartridge cases wiii project from their respective firing chambers to a greater extent than others and will therefore be forced" further therein by the fixed guide-means. Although such dimensional variations inthe length of the cases are exceedingly small, the resulting excessive crush? asit is referred; to in the art; will seriously affect ease of" extraction by causing the longer cartridge casesto stick-in their chambers. Similar stickingmay also be: encountered when the metal of the fired cartridge case expands in its firing chamberto such extent as to prevent the normal return to its original dimensions: In some instances of sticking; the extractor claw may even shear oi? the engaged portion of the fired cartridge case; The resulting failure to extract will createa dangerousjamming condition since the continued revolution ofthe drum' will bringa live round into position for ramming into the occupied chamber.-

(Dnemethcdof extraction now provided in the art for firearms of the typereferred to above comprises a fulcrumed lever arranged to actu ate a spring-biased pivotal extractor in such manner that the fired cartridge caseengagedthereby will first be loosened in its firing chamberand then flipped rearwardly' therefrom; These twosteps or extraction are accomplished by two adjoininginclined cam: surfaces provided in thereciprocableslide member employed to actuate the fulcrumed lever during counterrecoill While such design functions satisfac- Howtori ly; the work performed by the slide tends to decrease the speed of counter-recoii thereof and thereby detracts from the optimum rate of fire oi the firearm.

It is therefore an object of the present inven*-- ti'orr t'o ihcrea-se the rate of fire inautomatic-firearmsof the revolvertype wherein a counter recoiling slide a'ct'uatesa cartridge extractor by providing improved means for loosening a fired" cartridge case in its chamber independently of the slide and extractor movement's;

it is a further object or this inventiontir providein automatic firearms of the revolver type improved means for automatically effecting the same amount of primary extraction on a fired; cartridge regardless of the degree to which such case may tend to stick'irr its firing chamber.-

A specific object of the present invention: resides" in the provision, of a simple automatically operated device for loosening a. fired cartridge case in its chamber immediately prior to the actual extraction therefrom.

The specific. nature of the inventionv as well as other. objects and. advantages. thereof will. clearly appear from. the following description; of. arpreferredembodiment as. shownin the ac-' companying drawing in. which:

Fig, 1% is arear end viewof; the revolving drum and; the support: therefor showing, the locatiom oi. cartridge: loosening means relative: to the extractor;-

2- is-afragmentarytop viewof-Fig. 1 show ing the extractor in contact with its actuating lever;

Fig. 3 1s a fragmentary right side view of 1 in partial cross-section showing the slide in position to actuate the extractor lever and thereby the extractor; a

4 is a. fragmentary top view oi the. insertadapted to be secured to. the. rear drum support, and shows the. groove therein. for guiding; a

loosenedcartridge, case; into: engagementwiththm extractor;

Fig, 5 is: a front view of the; portion ofi the insert, shown in Fig; 4;

Fist 6: is a fragmentary: top view of theainsert;

fixedly:- mounted: in; the drum support and"- shows 55 drum-r Fig. 8 is an enlarged cross-sectional view taken along the line 8-8 in Fig. 1; and

Fig. 9 is a top view of the retracting plunger.

The present invention is particularly adapted for use in those automatic high speed firearms of the revolver type. Accordingly, a portion of one such firearm is illustrated in Figs. 1 and 3 and includes a revolving drum I2 having a plurality of firing chambers I3 annularly disposed equidistantly about the center thereof. A plurality of camming rollers I4 project from the outer periphery of drum l2 and are arranged to sequentially engage in a cam track (not shown) formed in a reciprocal slide I5 mounted immediately below drum I2. The contour of this cam track is such that the recoil and counter-recoil movement of slide l5 imparts a continuous rotation to drum A substantially U-shaped bracket I6 is fixedly secured in the firearm with the open portion thereof facing forwardly. Drum I2 is rotatably mounted between two fixed centers comprising a bearing portion II projecting upwardly from the rear end of bracket I6 and a front bearing (not shown). The rear end of bracket I6 also houses a firing mechanism I8 located immediately below bearing portion I1 as best shown in Fig. 1. Firing mechanism I8 is arranged to operate electrically whenever drum I2 rotates a round into contact therewith.

Fixedly secured to bracket I6 is a housing I9 having an extractor pivotally mounted therein as by a pin 2I. The outer end of extractor 20 is provided with a claw 22 arranged to engage in the annular extractor groove 23 of the present day type of cartridge cases 24 and bear against the rim 39 thereof. A lever 25 is vertically mounted to bracket I6 for pivotal movement. The upper end of lever 25 is arranged to contact extractor 20 while the lower end projects into the path of movement of a stepped shoulder 25 formed in slide I5. During the counter-recoil of slide I5, shoulder 26 thereon pivots lever 25 to actuate extractor 29 for flipping the fired cartridge case 24 out of firing chamber I3. A spring 21 biases extractor 20 forwardly to return claw 22 thereon to the position wherein the next cartridge case 24 will engage therewith.

In order to ease the work of extractor 20, the present invention provides a plunger 28 for loosening each fired cartridge case in its firing chamber immediately prior to engagement with extractor 20. Plunger 28 is slidingly seated in a recess 29 cut across the rear end of bracket I6 and located between firing mechanism I8 and extractor housing I9. The rear end of recess 29 is blocked by a plate 3|] fastened to bracket I6 as by screws 3 l. A spring 32 is seated within plunger 28 and acts against plate to continually bias plunger 28 forwardly. The front end of plunger 28 is arcuate in shape as best shown at 33 in Fig. 9 for a purpose to be disclosed.

An insert is secured to the front face of bracket I6 as by screws M and such insert is provided with a transverse recess 42 aligned with recess 29 in bracket I6 for permitting passage of plunger 28 into contact with the rear face of drum I2. Rearwardly of arcuate end 33, plunger 28 is provided with a transverse groove 34 having diverging side walls at one end thereof as best indicated at 35. Insert 40 is provided with a similar groove 36 extending substantially at right angles from recess 42 therein. Groove 36 is located so as to axially align with groove 34 when plunger 28 is forced rearwardly to abut plate 30.

In order to force plunger 28 rearwardly, a plurality of raised cam portions 31 are circumferentially disposed on the rear face of drum I2 adjacent the peripheral edge thereof. Each cam portion 37 is provided with a substantially flat top surface 38 as best shown in Fig. 7. As drum I2 rotates, surfaces 38 sequentially contact the arcuate end 33 of plunger 28. Cam portion 31 is so located relative to each firing chamber I3 that a line drawn through the center thereof from the center of drum I2 will bisect fiat surface 38.

In the operation of the firearm, cartridge cases 24 are sequentially rammed into each of firing chambers I3 as drum I2 revolves. Then, as each cartridge case 24 approaches the firing position, chambering is completed by contact thereof with the front face of firing mechanism I8. Firing then takes place and continued rotation of drum I2 brings the cartridge case rim 39 into groove 34 of plunger 28 as best shown in Fig. 8. The diverging side walls 35 of groove 34 serve to properly guide cartridge rim 39 therein. By this time, drum I2 has revolved sufiiciently to bring one of cam portions 31 thereon into contact with the arcuate end 33 of plunger 28. Thus, plunger 28 is depressed sufficiently to abut plate 30 during the period of contact between the flat top surface 38 of cam portion 31 and plunger end 33. Since cartridge case rim 39 is engaged in groove 34, the entire case 24 will be pulled sufiiciently rearward to become loosened in firing chamber I3.

As drum I2 continues to revolve, cartridge case rim 39 rides out of groove 34 and into groove 39. By this time cam portion 31 has moved out of contact with plunger end 33 thereby permitting spring 32 to return the plunger 28 to the unretracted position. Groove 36 guides cartridge case rim 39 into the correct position for extraction which is effected as previously explained.

Thus, there is here provided a simple yet positive device for loosening a cartridge case in the firing chamber of a revolver type firearm immediately prior to the normal extraction therefrom. The relatively large area of engagement between cartridge case rim 39 and groove 34 in loosening plunger 28 effectively prevents portions of rim 39 from being sheared off during the initial extracting movement of those cases which tend to stick in chamber I3.

Furthermore, by relegating the work of initial extraction to a member independent of the extractor, the inclined cam surfaces heretofore formed in reciprocable slide are no longer necessary and can be converted to the simple rightangled step 25 shown in Fig. 3. Accordingly, the previous frictional drag between the slide and the lower end of the extractor lever 25 is virtually eliminated. At a result, the slide will be enabled to counter-recoil with greater rapidity than heretofore thereby appreciably increasing the rate of fire of the firearm.

We claim:

1. In a firearm having a front and rear fixed support and a drum rotatably mounted therebetween, the drum having a plurality of annularly disposed firing chambers wherein cartridges are sequentially loaded for firing, the combination of a spring-biased retracting plunger slidably mounted in the rear drum support, said plunger having an arcuate front end and a transverse groove disposed rearwardly of said arcuate end for receiving therein the rim of a fired cartridge case as the drum revolves, a plurality of raised cam portions annularly disposed about the rear face of the drum, each of said portions being v aligned with one of the firing chambers and arranged to contact said arcuate front end of said plunger immediately subsequent to the engagement thereof with the rim of the fired cartridge case whereby said spring-biased plunger is cammed rearwardly to loosen the fired cartridge case in its firing chamber, and means for extracting the loosened cartridge case from the chamber.

2. In a firearm having a revolving drum provided with a plurality of annularly disposed firing chambers and means for sequentially loading cartridges therein, the combination of, a retracting plunger having a groove therein for receiving the rim of a fired cartridge case as the drum revolves, cam means for retracting said plunger relative to the rear face of the drum whereby the fired case is loosened in its respective firing chamber, an extractor, means for guiding said loosened cartridge case out of engagement with said plunger and into position for engagement by said extractor, and means for actuating said extractor to completely withdraw the loosened cartridge case for its firing chamber in the drum.

3. In a firearm having a revolving drum mounted between front and rear fixed supports and a plurality of annularly disposed firing chambers therein for receiving cartridges to be fired, the combination of a plunger slidably mounted in the rear drum support, said plunger having an arcuate front end and a transverse groove therein for receiving the rim of a fired cartridge case, a plurality of fixed cam portions projecting rearwardly from the rear face of the drum, each cam portion being disposed in axial alignment with one of the firing chambers and having a fiat top surface, spring means for biasing said plunger forwardly into contact with the rear face of the revolving drum whereby said plunger is cammed rearwardly to loosen the fired cartridge case in its chamber, an insert fixedly secured to the front face of the rear drum support, said insert having a substantially rectangular recess therethrough for permitting slidable passage of said plunger and a groove normal to the transverse axis of said recess, said plunger being positioned to align said groove therein with said groove in said insert during the period of contact between said arcuate end of said plunger and said flat top surface of said cam portion whereby the fired cartridge case engaged by said plunger is guided into engagement with said recess in said insert, a pivotal extractor mounted on the rear drum support in position to engage the rim of the loosened cartridge case emerging from said insert groove as the drum revolves, and means for actuating said extractor to completely withdraw the case from the firing chamber.

CHARLES H. STEVENS. KARL W. MAIER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,834,410 Loomis Dec. 1, 1931 2,366,840 Dobremysl Jan. 9, 1945 FOREIGN PATENTS Number Country Date 20,275 Great Britain 1914

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