US2587460A - Selective fire converter for semiautomatic firearms - Google Patents

Description

A. F. GAIDOS Feb. 26, 1952- F iled Sept. 27, 1950 5 Sheets-Sheet l INVENTOR. yaponzo 3 emnos fiTTORNEY n v v N T w mm mm mm g? 8 Wm mv n; i o fl/YV/Au 2.2%:52.5% QU Ji l I Iii/Z155 @N A. F.. GAIDOS Feb. 26, 1952 SELECTIVE FIRE CONVERTER FOR SEMIAUTOMATIC FIREARMS 5 Sheets-Sheet 2 Filed Sept. 27, 1950 A. F. GAIDOS Feb. 26, 1952 SELECTIVE FIRE CONVERTER FOR SEMIAUTOMATIC FIREARMS 3 Sheets-Sheet 5 Filed Sept. 27, 1950 Patented Feb. 26, 1952 UNITED stares PATENT iOFFlCE JSELECTIVE FIRE CONVERTER FOR SEMIAUTOMATIC FIREARMS Alonzo F. Gaidos, Redwood City; Calif. .;.Apiplication September 27, 1950, Serial No. 187,035

' '16 Claims. 1 I I This invention relates. to. a selective-fire. con- .verter which maybe attached-tea. semi-automaticfirearm to provide forsemi-automaticfire or full automtaic fire at themselectionvof the marksman.

. Heretofore, several selective fire converters have-been developed for attachment to the U..S. carbine, caliber-30M1 largequantities of .which -.are-now stored. As originally designed-and-dis- ..closed in Humeston Patent No. 2,308,283,;this Weapon is fired semi-automatically, that is, a pull onthe trigger. fires. a .single round, reloads a .shell in the chamber. and cocksthe firing mechanism. .Tofire a second round, the triggermust-be re- --leased and again pulled. .Two of the. previously developed selective .fire. converters .are disclosed in my co-pending applications, Serial.No.- 730,2L4, filed October 16, 1947,..and.-Serial. No. 138,766, filed January 16, .1950. The .convertersTdisclosed in these co-pending. applicationsare-itheonly ones which accomplish thegdesired. result ,without-modifying or remachiningv operating partsof the basic weapon. vThepresent invention .isan

improvement upon the selective'fireconverters disclosed in these co-pending patent applications.

.-A majorobject of this invention is' to provide a selective fire converter, having a simplified mechanism whichis easier to install and maintain. An important object ,ofithe. inventionis ;to provide a. selective .fire, converter? having com- .ponent partswhich may be. more economically manufactured.

' In the attainment of theseobje'cts, oneifeature of the invention resides in. the. construction of. a sear tripper .which .is'mounted on" the pivot pin l- .for .the hammer and is operated by a sliding ac- .l tuator .barl arranged to be reciprocated? by'tthe automatically reciprocating slide 'of' the .weapon. .This sear tripper has a rearwardly extending portion with a sear engagingf foot extending downewardly tooverlie the sear, and an upwardly 18X- tending actuating projection disposed in the path of .the actuator bar. Another feature of themverition resides .in the arrangement of anactuating member connected by a pivot totheend of the actuator bar and resiliently urged away fromithe actuating projection on the seartripper. The actuator bar .and actuating member slide" in a1 guidewayformed by a casing attached'tothe receiver bythe same bolt which secures the trigger. housing to the receiver. #Slidableinthis same casing is a selector having a'cam' forishifting the i actuating member aboutits pivot towardthe ac- "tuating projection on the sear tripper.

Other objects and advantages of thefinvention;

will become apparent from "the following-specification taken in connection with .the accompanying drawings wherein;

Figure 1 is a vertical sectional view'of' a carbine illustrating a preferred embodiment; of the invention with some parts broken awayforpurposes of clearness;

Fig. 2 is a top plan view of the carbine with some parts broken :away' and others showni-in section;

Fig. 3 is a side elevation of the carbine with the selector in its automatic position; some parts being broken away and others shown in 'section;

Fig. 4 is a fragmentary'vertical sectional view of the firing mechanism withsome parts broken away and others shown-in sectin,'"the'parts being shown in" positions assumedafter the trigger is pulled and the hammer has moved to firing position;

Fig. 5 is a vi'ew'similar'toFig. 1- butshowing the slide. and. bolt retracted to cock the hammer;

' Fig. 6 'is a view similar to Fig. 4 showing "the parts inv cocked position with the slide and bolt partially returned to battery position;

Fig; 7 'is a" fragmentary horizontal sectional view of the firing mechanism shown in'Figi 3;

Fig. 8 is a partial top plan'view illustrating the arrangement of the selector;

Fig. 9-is a partial sectionalview taken on the line 9-9 of Fig. 7;

Fig. 10 is a'fragmentary view similar-to'Figi 3,

Fig; 11 is a perspective view or the sear-tripper; and

Fig. 12 is a perspective view ofthe actuatin member on the end of the actuator bar.

A"U. S. carbine, caliber'.3.0M1 has areceiver '2! in the 'forwardend of which a barrel 22 is threaded. Locked by a dovetail joint 23- at the rear of the receiverand a transverse bolt 24 at the forward end of the receiver is a trigger housing 25 arranged below the receiver. This housing 25--is formed witha recess 26 in its central portion. -A hammer pin 21, extending across the recess 26, pivotally supports a hammer '28 which *moves-in an arcuate path between a cocked position, as shown in Fig. 1; and a discharge. or firing position; as shown in Fig. 4. This hammer 23 hasone side formed with a-recess" 3| (Figs. 2 and 7) extending between its front end 32 and-its rear end 33.

Extending across the recess-2B rearwardlyof hammer pin 27 is a sear pin 34. A trigger 35 has a pair of ears =one of-which is illustrated at 36,

extending upwardly through an opening 31 in the bottom of the trigger housing and pivoted on the sear pin 34. Trigger 35 has a rearwardly extending portion 38 above which 39. Normally urging the trigger 35 in a counterclockwise direction as viewed in the drawings is a wire spring 40 secured to the trigger housing. Arranged between the ears on the trigger is a projects a lip sear 4| formed with an elongated transverse slot 42 through which sear pin 34 is inserted permitting pivotal movement of the sear 4| about the pin 34 and longitudinal shifting movement of the sear with respect to the pin. Extending forwardly from the slot 42, sear 4| has a hammer engaging nose 43 arranged to cooperate with notch 44 in the lower part of hammer hammer in cocked position. Trigger engaging seat 45 provides a rearward extension on the sear I 4| arranged, when the sear is in rearward position as indicated in Fig. l, to rest on lip 39 onthe trigger 35,. and, when the sear is in its forward position as indicated in Fig. 6, to rest on the upper surface of the rearwardly extending portion 38 on the trigger. 35. Normally urging sear 4| in a forwardly direction is a spring 46 retained in a cylindrical recess 4'! formed in portion 38 of the trigger 35 and bearing upon a shoulder 48 extending downwardly from seat 45 on the sear The construction thus far described is the standard design of the U. S. carbine, caliber .30M1. With the hammer cocked, a pull on trigger 35 acts by engagement of lip 39 with seat 45 on the sear to shift nose 43 out of engagement with notch 44 and permit hammer spring 5| to move the hammer 28 to firing position, as' illustrated in Fig. 4. Then, the explosion of the ammunition produces gases under pressure which act on piston 52 incylinder 53 to move slide 54 rearwardly causing bolt 56 to ride over the top part of hammer 28, as illustrated in Fig.5. As the slide 54 and bolt 56 return toward battery position, as illustrated in Fig. 6, notch 44 in hammer 28 is engaged by nose 43. If trigger 35 is retained in its pulled position, as illustrated in Fig. 6, seat 45 rests upon the uppersurface of the trigger portion 38 and bears against the forward end of lip 39 thereby retaining the hammer 28 in cocked position. To again fire the weapon, trigger 35 must be released permitting seat 45 on sear 4| to move rearwardly above the lip 39. Then, a subsequent pull on the trigger will move the sear in the same fashion as already described.

With a selective fire converter attached to the weapon it may be fired semi-automatically in the same fashion as the basic weapon, or it may be fired automatically in a manner to be described where it will repeat the firing cycle as long as a pull is exerted on the trigger but will stop firing immediately upon release of the trigger.

One component of the selective fire converter is a sear tripper designated generally at 6| and illustrated in perspective in Fig. 11. This sear tripper 6| has a body portion 62 from which depends an ear 63. A transverse arm 64 extends from the body portion to support another depending ear 65. These car 63 and 65 are arranged in parallel relation and spaced apart a distance corresponding to the outside widths of the trigger housing at the hammer pin 21. Both ears are provided with alined holes like the hole 66 in the ear 63 so the sear tripper may be pivotally mounted on the end portions of the hammer pin 21 which project through the walls of the trigger housing. Body 62 of the sear tripper 6| 28 to retainthe 1 tion,

has an inwardly offset portion 61 to which is attached a rearwardly extending arm 68. Thi arm isrelatively thin and generally of arcuate shape lengthwise so it will lie within recess 3| and pergaging foot 69 arranged to overlie a raised shoulder or step H on the upper surface of nose 43 on sear 4|, when the sear is in its forward posias illustrated in Fig. 6. When the sear is in its rearward position, as illustrated in Fig. 1, foot 69 is disposed forwardly with respect to step Extending upwardly from arm 68 is an actuating projection 12 having'at its top a cam surface 13 for a purpose to be described. Actuating projection 12 is normally urged upwardly by a spring 10 connected to the trigger housing and tending to turn the sear tripper in a counterclockwise direction as viewed in the drawings.

Mounted on the side of the receiver 2| is an elongated casing 14 secured by threaded engagement of depending flange 15 with the same bolt 24 which connects the trigger housing and the receiver. At its rear end, casing 14 has an inwardly projecting hook shaped lug 16 which engages in a recess 11 at the back of the receiver above dovetail joint 23. Casing 14 has a flat exposed side with upper and lower inwardly projecting flanges and 80' forming a guideway along the side of receiver 2|. Slidable in this guideway is an actuator bar 18 having its forward part I9 offset outwardly at 8| and extending beside the path along which slide 54 reciprocates. At its front end, forward part 19 of bar 18 is turned inwardly to form an abutment 82 which is engaged by forward edge 83 of the slide 54. Rearward edge 84 of the slide 54 engages front edge 85 of the receiver to arrest rearward movement of the slide. This rearward edge 84 of the slide 54 has an undercut edge 86 which engages an abutment 81 formed on the inner face of actuator bar 18 just rearwardly of offset 8|.

When the slide 54 is in its most forward position, as illustrated in Fig. 3, the distance (indicated by dotted line A) from rearward edge 84 of the slide to forward edge 85 of the receiver is slightly greater than the distance (indicated by dotted line B) from undercut edge 86 on the slide 54 to abutment 81. Upon reciprocation of the slide 54in a rearward direction, undercut edge 86 engages abutment 84 to move actuator bar 18 a short distance rearwardly from its position, as shown in Fig. 3, to the position shown in Fig. 5, where rearward edge 84 of the slide 54 engages forward edge 85 of the receiver 2|. Then, return of slide 54 to its forward position will reverse the sliding movement of the actuator bar just as the slide returns the bolt 56 to its battery position, as illustrated in Fig. 7. This limited reciprocating movement of the actuator bar produces a pivotal movement of the sear tripper by means of the actuator mechanism now to be described.

As illustrated in Fig. 10, rear end of actuator bar 18 is provided with an inwardly ofiset end portion 9| to which is connected by pivot pin 92 an actuating member 94. Actuating mem ber 94 has a horizontal flange 95 extending inwardly and rearwardly. At the back of the flange 95 is a cam 99 arranged to ride over cam surface 13 on actuating projection 12 of the sear tripper when actuator bar 18 is reciprocated by the slide 54. Wire spring I0 I, which is wound e on-'- pivot 92 is: arranged to -act between bar n and amember 94 *to resiliently I 'urge actuating member 94 *with its: cam 99 about the: pivot "92 away fromactuatingproj ection 2 on "the seartrippent I :Forwaidmovement bf theactuator' -..bar -18 is limited by a lug '9 textending inwardly from the bar 18- and'arranged'to-em age .W'all 98 in the receiver.

Slidable atthe rear endof casing ldis a' selector -I02having a body portion I03 -slidable in opening IM 'formedin the upper flange B of the ca'sing. i1 Forwardly extending fingers I 05 and I BB are sepa- --rated a distaneeequal to the thickness offiange 80 so theyv slidealong the upper and lowersurfaces of the flange. On rearwardly extending portion 101 is an operating 1 flange I 08 having a knurled surface accessible *to the thumb of the marksman-so T the selector may 7 be shifted-forward or backward. A spring 199 e extends rearwar'dly 'mer 128 to again "fire theiweapon andfrepeatithe same- "-cyc-le. This: automatic cycle continues. to repeat untillthe trigger -35 is released. Themzas the slide movesactuat-onbar 18 forwardhc'to'gde- 5 press the sear. tripper.: :foot i69 :wm :bedepressed -in front of raised step 1 I. because; upon release .ofrthe-trigger the sear will move. .to its rearward position; as illustrated'in Fig. .1.

-When semieautom'atic. operation of I the: weapon' is desired, the operator moves .serratedflange l-fla rearwardly to shift selectoruIIlZ. to. its rear- 1 ward 'or semi-automatic position with detentIIl9 engagedin opening H2. 'Ihismovementbf the selector -moves cam surface I I 0 out ofz'engage- =ment with cam surface II I soothe; actuating member-94': pivots away from the sear :trippen-sso :icam 99 is withdrawn from-a position whererzit will-engage cam surface 13 on: the sear tripper. A pull on the trigger will cause the gun to "fire vfrom body portion 402 and has links arranged 2O-"and the slideand bolt tocock the hammer. .Z-Reto enter openings inxthe fiange'fic- .to serve as a'detent for the selector. -With the selector I92 in forward-position so detent I09 'is engagedin opening I04, as indicated in Fig. 3, inclined cam ciprocationof the slide produces reciprocation r of the actuating bar 18, but reciprocation of. .the actuating member-Maud the cam 99fiisineiiec- .tive' because the camdoes not-engagesthe; actusurface III onthe bottom. of fiangeIiiS engages'25'atingprojection on the sear tripper. Hence;:.the

a corresponding camsu'rface' II I von a'ctua ting member 94 to depress the actuatingmember so-a'ctuating projection 99 will engagecam sur- 1 face Won the sear tripper. Whenselector IilZ tweaponwill fire a single. shot and then' remain in cockedpositionauntil the. .triggenis released a andagain pulled.

It will beapparent that-.the...component parts "is shifted to-its rearward semi-automatic posi-BO: of the selective fire-converter .disclosed: =.herein tion. detent =I 09 engages opening I I2,.as indicated in Fig. 10. In this position inclined-cam surface I I IJ onthe selector is" disengaged from cam-sur- -="-face II I onthe -actuating member 94 thereby may be very. easilyzmanufactured. The. actuator bar 18: and the actuating .member ey'mayzbe stamped from metal stock. Asimple; rivetzipro- 'vides thepivot 95 connecting these two 1 parts.

permitting spring :Iflttoehift cam 99- u ar'diy e5 Likewise, sear tripper EIaandselector lllz may be 1S0 "it-will not-operate the sear tripper.

'Wi'th selector I02 in its forward or automatic position; as illustrated in fig 3,-= apull on the -'trigger removes searnose 4|. from-"engage ment with the hammer notch 44 so "the' gun will 40 firew'ithefirst round. -Exhau'stgases act-upon piston 52-:which moves slide 54 ='rea1'wardlyso bolt '56 cocks hammer 28;- as"illu'stratedin'Figf- 5. Asrthe slide approaches itsrearmostpos'ition, undercut edge 8B'engages' rear-.ab'utmentBl on; the actuator bar to reciprocate the bar and actuating member 94 rearwai-dly. Further rearward xmovement= of theslide 54, until rearward edge '84 engages forward edge-'85 of the receiver; re-

-*ciprocates theactuator bar 18 rearwardly -andzgg thereby' moves cam' 99" rearwardly with respect it to-cam surface 13 on=actuating projection 72. This rearmost position'of' rthe :c'am fsa is illus- -trated in Figs. 5 andh6, and: in"'dottedlines:in

Fig. 1.

When' the slide-and boltmove-"forwardly to- :wvard battery. position; hammer 28 is retained in cockedposition'by engagement of nosel'43 on the sear. with notch i on the hammeneasillusmade on stamping: machines. To incorporate this ==selective fire converter in ;.a standardircarbine, itis only-.necessaryirtoreplace'xthe.seaii' in the carbine with .a sear .havingzazraisedstep :II on its hammer engaging nose. '1 Thehammer pin xis removed and an. elongatedhammer pin 21 is insertedwith thesear tripperiinzplace. Actuator bar- 18 andselector I82 are-.assembled'in casing T i l-and secured by transverse. screw 24 whiclrreplaces the'pin in; the. standard :carbine. Thus, the component parts are .not only economically manufactured but may be quickly-assembled-by a soldier in'the field-and very easily maintained.

Whatis claimed ;is: 1.'-An automatic firearm =comprising. .a. re- -"ceiVer,-'-a trigger housing'an automatically "reciprocatingslide--on said receiver; ahammerr. pin iaextending. through. said housing; a hammer piv- 'otedonrsaid-pin, a-trigger pivotally mountedarin said housing".aseaInhaving-an elongated slot;- a pin extending through .saidslct. and mounted :in .::said housing, .arforwardly extending hammer engaging noseon said sear. arranged. to cooperate with a notch :in: 'sa'id uhammer. and: retaini'said tratedinFig; 6. At-this point, the sear is-Tetfiinedm h m r nr c p r p n win. its forward position-byengagement 'of sear -:seat 38-with'lip 39 on the triggerp-Th-us; the" sear :engaging: foot-'- [i9 on the sear tripper overlies braised step II on' the sear.

nose, a rearwardly extending" trigger engaging .iseat :on :said sear soverlying said trigger, a scar .xtripper.epivoted on said; hammer. pin, sear engaging foot on: said tripper. overlying saidt-zstep,

As the slide and bolt return tobattery posi-g anupwardly extending:actuating projectionpn -.-.tion, forward edge 83 on thes slide engagesabutment 82 on the forward end *ofthe actuator bar i to move the actuator bar with actuating member :1942andx cam. 99.? forwardly. lWith: 'this. forward z said.seairtripper,v an. actuator bar reciprocablesby .zsaid rslideyand an actuatingsmember-onusaidmar arranged: to: *engageqsaid. projection andy. .move said-.sear'tripp-er in amanner causing saidncse movementr'of theactuating 'member;-.c am; SSi de- 47 -tc depressisaid sear.

presses oam surface 13' one-actuating projection I2 against the force of spring-':'Ifl; thereby pivot- .1 :ing the sear tripper" 6 l about the-hammer pinZI and depressingv foot .69. onto raisedstep :7 lwonithe .ssear and depressing. the sear toreleasethzham+ 2. An 1 automatic lzfirearm comprising a .r're- -:.c'eiver,1.a trigger housing; an. automatically.;:-re-

.=zciprocatingoslide'. on said receiver; a hammertpin extendingxthrouglrsaid housing,ra hammer fpivlmed;onisaidpinpalitriggerspivotally.mcuntedqin said housing, a sear having an elongated slot, a pin extending through said slot and mounted in said housing, a forwardly extending hammer engaging nose on said sear arranged to cooperate with a notch in said hammer hammer in cocked position, a raised step on said nose, a rearwardly extending trigger engaging seat on said sear overlying said trigger, a sear tripper pivoted on said hammer pin, a sear engaging foot on said tripper overlying said step, an upwardly extending actuating projection on said sear tripper, an actuator bar reciprocable by said slide, an actuating member on said bar arranged to engage said projection and move said sear tripper in a manner causing said nose to.

depress said sear, and a movable selector connected with said actuating member for shifting said member relative to said actuating projection.

3. An automatic firearm comprising a-receiver,

an automatically reciprocating slide on said receiver, a hammer pin extending through said housing, a hammer pivoted on said pin, a trigger pivotally mounted in said housing, a sear having an elongated slot, a pin extending; through said slot and mounted in said housing, a forwardly extending hammer engaging nose on said sear arranged to cooperate with a notch in said hammer and retain said hammer in cocked position, a raised step on said nose, a rearwardly extending trigger engaging seat on said sear overlying said trigger, a sear tripper pivoted on said hammer pin, a sear engaging foot on said tripper overlying said step, an upwardly extending actuating projection on said sear tripper, an actuator bar reciprocable by said slide, and an actuating member pivotally connected to the end of said bar to engage said projection and, move said sear tripper in a manner causing said nose to depress said sear.

4. An automatic firearm comprising a receiver, a trigger housing, an automatically reciprocating slide on said receiver, a hammer pin extending through said housing, a hammer pivoted on said pin, a trigger pivotally mounted in said housing, a sear having an elongated slot, a pin extending through said slot and mounted in said housing, a forwardly extending hammer engaging nose on said sear arranged to cooperate with a notch in said hammer and retain said hammer in cocked position, a raised step on said nose, a rearwardly extending trigger engaging seat on said sear overlying said trigger, a sear tripper pivoted on said hammer pin, a sear engaging foot on said tripper overlying said step, an upwardly extending actuating projection on said sear tripper, an actuator bar reciprocable by said slide, an actuating member pivotally connected to the end of said bar, and a movable selector for shifting said actuating member relative to said actuating projection.

5. An automatic firearm comprising a receiver, a trigger housing, a bolt securing said housing to said receiver, an automatically reciprocating slide on said receiver, a hammer pivotally mounted in said housing, a trigger pivotally mounted in said housing, a sear having an elongated slot, a pin extending through said slot and mounted in said housing, a forwardly extending hammer engaging nose on said sear arranged to cooperate with a notch in said hammer, a raised step on said nose, a rearwardly extending trigger engaging seat on said sear overlying said trigger, a sear tripper pivotally mounted on the pin for said hammer. a sear engaging foot on a trigger housing,

and retain said said tripper overlying said step, an upwardly extending actuating projection on said sear tripper, a casing extending along the side of said receiver and secured thereto by said bolt, an actuator bar slidable in said casing and reciprocable by said slide, and an actuating member pivotally connected to said bar and arranged to engage gated slot, a pin extending through, said slot 7 and mounted in said housing, a forwardly extending hammer engaging nose on said sear arranged to cooperate with a notch in said hammer, a raised step on said nose, a rearwardly extending trigger engaging seat on said sear overlying said trigger, a scar tripper pivotally mounted on the pin for said hammer, a sear engaging foot on said tripper overlying said step, an upwardly extending actuating projection on said sear tripper, a casing extending along the side of said receiver and secured thereto by said bolt, an actuator bar in said casing reciprocable by said slide, an actuating member pivotally connected to said bar, and a selector member mounted on said casing for shifting said actuating member relative to said actuating projection.

7 An automatic firearm comprising a receiver, a trigger housing, a bolt securing said housing to said receiver, an automatically reciprocating slide on said receiver, a hammer pivotally mounted in said housing, a trigger pivotally mounted in said housing, a sear having an elongated slot, 3, pin extending through said slot and mounted in said housing, a forwardly extending hammer engaging nose on said sear arranged to cooperate with a notch in said hammer, a raised 'step on said nose, a rearwardly extending trigger engaging seat on said sear overlying said trigger, a sear tripper pivotally mounted on the pin for said hammer, a sear engaging foot on said tripper overlying said step, an upwardly extending actuating projection on said sear tripper, a casing extending along the side of said receiver and secured thereto by said bolt, an actuator bar slidable in said casing, spaced abutments on the forward end of said bar engageable by said slide to reciprocate said bar, and an actuating member on said bar arranged to engage said actuating projection.

8. In an automatic firearm having a hammer pivotally mounted on a hammer pin, a scar for engaging a notch in said hammer, and an automatically reciprocating slide for cooking said hammer, a selective fire converter comprising a sear tripper pivotally mounted on said hammer pin, a sear depressing foot on said sear tripper overlying said sear, an actuating projection on said sear tripper, an actuator bar reciprocated by said slide, and an actuating member on said bar arranged to engage said actuating projection upon reciprocation of said bar.

9. In an automatic firearm having a hammer pivotally mounted on a-hammer pin, a sear for engaging a notch in said hammer, and an automatically reciprocating slide for cocking said hammer, a selective fire converter comprising a sear tripper pivotally mounted on said hammer pin, a sear depressing foot on said sear tripper overlying said sear, an actuating projection on 9 said sear tripper, an actuator bar reciprocated by said slide, an actuating member pivoted on said bar, and a movable selector connected to said member for shifting said member relative to projection.

10. In an automatic firearm having a hammer pivotally mounted on a hammer pin, a sear for engaging a notch in said hammer, and an automatically reciprocating slide for cooking said hammer, a selective fire converter comprising a sear tripper pivotally mounted on said hammer pin, a sear depressing foot on said sear tripper overlying said sear, an actuating projection on said sear tripper, an actuator bar reciprocated by said slide, an actuating member pivotally connected to the end of said bar, spring means resiliently urging said member from a position to engage said projection upon reciprocation of said bar, and a movable selector connected to said member for shifting said member against said spring means to a position to engage said projection.

11. In an automatic firearm having a hammer pivotally mounted on a hammer pin, a scar for engaging a notch in said hammer and an automatically reciprocating slide for cooking said hammer, a selective fire converter comprising a sear tripper pivotally mounted on said hammer pin, a real-wardly projecting arm on said sear tripper, a sear depressing foot extending downwardly from said arm to overlie said sear, an actuating projection extending upwardly from said arm, an actuator bar reciprocated by said slide, and an actuating member on said bar arranged to engage said projection and move said sear tripper to depress said sear.

12. In an automatic firearm having a hammer pivotally mounted on a hammer pin, a scar having an elongated slot permitting longitudinal shifting of said sear on a pin through said slot, a raised step on the hammer engaging nose of said sear, and an automatically reciprocated slide for cooking said hammer, a selective fire converter comprising a sear tripper pivotally mounted on said hammer pin, a rearwardly projecting armon said sear tripper, a sear depressing foot extending downwardly from said arm and overlying said step only when said sear is shifted forwardly, an actuating projection extending upwardly from said arm, an actuator bar reciprocated by said slide, and an actuating member on said bar arranged to engage said projection upon reciprocation of said bar.

13. In a selective fire converter for an automatic fire arm having a trigger housing, a hammer pivotally mounted therein, a sear for engaging said hammer, an automatically reciprocated slide for cooking said hammer, and an actuator bar .reciprocated by said slide; a sear tripper comprising a body, a first ear depending from said body, a transversely extending portion on said body, a second car depending from said portion parallel to said first ear and spaced therefrom a distance corresponding to the outside width of the trigger housing, said ears being formed with alined holes to mount said sear tripper on the pivot pin for said hammer, a rearwardly extending arm on said body, a sear engaging foot extending downwardly from said arm, and an actuating projection extending upwardly from said arm to be engaged by said actuator bar.

14. In a selective fire converter for an automatic fire arm havinga trigger housing, a hammer pivotally mounted therein, the hammer being formed with a longitudinally extending recess in one side, a sear for engaging said hammer, an automatically reciprocating slide for cooking said hammer, and an actuator bar reciprocated by said slide; a sear tripper comprising a body, a first ear depending from said body, a second ear depending from a transversely extending portion of said body parallel to and spaced from said first car a distance corresponding to the outside width of the trigger housing, said ears being formed with alined holes to mount said sear tripper on the pivot pin for said hammer, an arcuately shaped rearwardly extending arm inwardly offset from said first ear to lie within the recess in said hammer and permit relative movement of said sear tripper and said hammer on the pivot pin for said hammer, a sear engaging nose depending from said arm, and an actuating projection extending upwardly from said arm into the path of said actuator bar.

15. In a selective fire converter for an automatic firearm having a pivotally mounted ham;

mer, a sear for engaging said hammer. an automatically reciprocating slide for cooking said hammer and a pivotally mounted sear tripper for depressing said sear; actuator mechanism comprising a longitudinally extending casing, an actuator bar slidably mounted in said casing along the path of said slide, spaced abutments on said actuator bar engageable by said slide to reciprocate said bar, an actuating member pivoted to the rear end of said actuator bar, spring means resiliently urging said member away from said sear tripper, and a selector slidable on said casing to move said member toward said sear tripper against the force of said spring.

16. In a selective fire converter for automatic firearms, actuator mechanism as defined in claim 15 wherein said selector has a cam engageable with said actuating member to move said member about said pivot against the action of said spring means.

ALONZO F. GAIDOS.

No references cited.

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