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INVENTOR. azowzo A. Gazoo3. Patented Aug. 18, 1953 2,649,030

UNITED STATES PATENT OFFICE 2,649,030 SELECTIVE FRE CONVERTER FOR SEM AUTOMATIC FREARMS Alonzo F. Gaidos, Redwood City, Calif. Application January 16, 1950, Serial No. 138,766 Claims. (C. 89-40) 2 This invention relates to a selective fire Con Other objects and advantages of the invention verter which may be attached to a semi-auto Will become apparent from the following specifi matic firearm to provide either semi-automatic cation taken in conjunction with the accompany firing or full automatic firing at the selection ing drawings wherein: of the marksman. 5 Figure 1 is a partial side elevational view with Large quantities of the U. S. carbine, caliber Some parts broken away and others in Section, .30 M1 have been manufactured and are now of the receiver and trigger housing of a Semi-auto stored. This weapon, as disclosed in Humeston matic firearm to which the present invention may Patent No. 2,308,283, is designed for semi-auto be attached; matic operation. That is, a pull on the trigger O Fig. 2 is a similar view of a semi-automatic will fire a single round, reload a shell in the firearm to which is attached a Selective fire Con chamber and cock the firing mechanism, but verter embodying the invention in its preferred will not fire a second round until the trigger is form; released and again pulled. Fig. 3 is a partial elevation of the firearm and Several attempts have been made to modify converter shown in Fig. 2, as seen from the oppo the M1, caliber .30 carbine So it will fire automati site side, some parts being broken away and cally as long as the trigger is depressed, or, at Others shown in section for purposes of clearness, the selection of the operator, will fire semi-auto the selector being shown in automatic position matically. Of these conversion efforts, only the with the hammer cocked; Selective fire converter disclosed in my copend 20 Fig. 4 is a view of the firing mechanism similar ing patent application, Serial No. 780,214, filed to Fig. 3, with the trigger pulled and the hammer October 16, 1947, accomplishes the desired result moved to its fired position; without modifying or remachining operating Fig. 5 is a view similar to Fig. 3, after the fire parts of the basic weapon. The present inven arm is fired and showing the bolt and slide in tion is an improvement upon the selective fire 25 recoil position and the trigger retained in its converter disclosed in that patent application. pulled position; A major object of this invention is to provide Fig. 6 is a view similar to Fig. 5, with the bolt a selective fire converter of Simplified construc and slide returned almost to battery position; tion which may be attached to a semi-automatic Fig. 7 is a view similar to Fig. 6, with the bolt firearm without modifying, replacing, or rema 30 and slide completely returned to battery position, chining any operating parts of the firearm. and the hammer released to firing position; A particular object of the invention is to pro Fig. 8 is a partial view showing the parts por vide an effective converter having few parts, all sitioned similar to Fig. 3, but with the Selector in of which operate upon a bracket which may be semi-automatic position; attached to one side of the firearm. 35 Fig. 9 is a perspective view of the bracket and Another object of the invention is to provide associated parts of the selective fire converter a selector conveniently located So it may be read embodying the invention in its preferred form, ily shifted by the thumb of the marksman's right the housing being removed; hand. Fig. 10 is a perspective view of the housing In accordance with these objects, an important 40 forming a part of the selective fire converter; feature of my invention resides in the arrange Fig. 11 is a perspective view of the actuator ment of a bracket and housing for supporting bar forming a part of the invention; the complete converter on One side of the firearm. Fig. 12 is a side elevation of the selective fire A selector lever on the bracket may be shifted by converter with the housing removed; the marksman's thumb to automatic or semi 45 Fig. 13 is an end view of the bracket and a S automatic positions. Another feature resides in sociated parts as seen from the rear or right side the construction of an actuator bar having spaced of Fig. 12; abutments, one of which is adjustable longitudi Figure 14 is a perspective view of the selector nally of the bar, to be engaged by the reciprocat cam and its operating lever; and ing slide on the firearm and thereby reciprocate 50 Figure 15 is a horizontal sectional view of the the actuator bar. Still another feature resides front end portion of the actuator bar. in the provision of a pivoted end piece slidably In its preferred form, the invention includes a mounted on the bracket and engageable by one bracket secured by the hammer pin to one side of end of the actuator bar, which end piece is shift the firearm. Pivoted on the bracket is a Sear able between operative and inoperative positions 55 tripper movable from inoperative to operative by movement of the selector. position by the trigger and normally urged toward

2,649,080 5 6 ing 58 secured alongside the trigger housing by is formed as a bend in the bar. Forward abut hammer bolt 30'. This housing 58 has a for ment 8 preferably is a block having a Serrated Wardly extending portion 59 retained in posi surface 84 (Fig. 15) engaging a correspondingly tion by a transverse receiver bolt 22" Substituted Serrated Surface 85 on the forward end of actu for the pin. 22. An upper part 6 of forward ating bar 62. Abutment 8 may have an elon portion 59 is shaped to form a guideway So an gated slot 86 through which extends a bolt 87 actuator bar 62 may slide relative to the firearm threaded into the actuator bar 62. Once the and selective fire converter bracket 5 in the abutment 8 is adjusted to its proper position, guideway between the side of receiver 2 and the bolt 87 may be tightened to Securely retain the guideway 6 on the housing. At the rear end 0 abutment on the end of the bar. The abutments of actuator bar 62 is a hole 63 engaging an in 8 and 82 are so spaced and arranged with re wardly projecting pin 63 extending through a spect to the slide 25 and its path of reciproca longitudinally elongated slot 64 (Fig. 9) formed tion that actuator bar 62 is automatically recip in the upper portion of bracket 5. Preferably, rocated a distance shorter than the length of slot the pin has a loose fit with respect to actuator 15 64 in the bracket 5. bar 62 so the pin 63 may pivot with respect to In operation, with the selector lever 73 in its the bar. It will be apparent that pin 63 sliding automatic position and the hammer cocked as back and forth in slot 64 provides a guide for shown in Fig. 3, the marksman pulls trigger 39 So reciprocation of the actuator bar 62 With respect its lip 43 raises rear portion 42 of sear 34, thereby to bracket 5. Pivotally connected to the rear 20 removing sear nose 45 from hammer notch 33 end of actuator bar 62, which is slidably mounted and permitting hammer Spring 35 to move the on bracket 5 by pin 63 passing through slot 64, hammer forwardly and fire the gun. Pulling the is an end piece 65 which extends rearwardly trigger 39 also causes lip. 43 to engage and raise from the actuator bar 62 between the bracket trigger engaging foot 53 to turn Sear tripper 52 5 and its associated housing 58. End piece 65 25 clockwise, as viewed in Fig. 3, so actuating pro has an inwardly projecting ear 66 arranged to jection 54 is raised from its inoperative position, overlie and/or engage actuating projection 5. On as shown in Fig. 3, to its operative position, as the sear tripper 52. A tension Spring 67, which shown in Fig. 4. It will be noted that after the may be a continuation of the spring 56, is held gun is fired, as shown in Fig. 4, sear 34 moves on the bracket 5 by stud 68 and engages the 30 forwardly under the action of sear spring 4. upper side of ear 66 to yieldingly urge the ear After the gun is fired, explosion gases act on pis 66 downwardly, toward Sear tripper 52. Also, ton 26 to reciprocate slide 25 rearwardly. This pivoted on the bracket 5, as by pin 69, is a rear motion of slide 25 first causes bolt 3 to turn selector cam 7 having a cam Surface 72 (Fig. the hammer 32 to a position as shown in Fig. 5, 14) formed by bending the strip material of the 35 which is actually turned counter-clockwise be cam. Extending upwardly from the cann. It is a yond its cocked position, as illustrated in Fig. 3. selector lever 73. The cam has its calm Sur When the slide engages intermediate abutment face so arranged that end piece 65 may be raised 82 on the actuator bar 62, it reciprocates actuator or lowered by shifting the position of lever 3. bar 62 rearwardly in guideway 6 so pin 63 is . As illustrated in Fig. 2, Selector level T3 is in 40 moved rearwardly in slot 64 and end piece 65 is Semi-automatic position. In this position, can moved rearwardly. Inasmuch as actuating pro Surface 2 turns end piece 65 about its pivot 63 jection 54 on the Sear tripper 52 is raised to Oper thereby raising ear 66 to a position displaced ative position, and ear 66 is lowered to its auto above actuating projection 54 on Sear tripper 52. matic position, the ear 66 will engage the actu To retain the selector lever 3 in semi-automatic ating projection 54. As the actuator bar 62 position, housing 58 is formed with a notch 75 continues to move rearwardly, ear 66 Will over in its rin S (Fig. 10). This provides a detent ride the upWardly sloping Surface of actuating to retain the Selector lever in its semi-auto projection 54 and will thereby be raised against natic position. Movement of selector lever 3 the action of spring 67. Continued rearward from the position shown in Fig. 2 forwardly or movement of slide 25 will move the actuator bar counter-clockwise, as viewed in Fig. 2, to a posi 62 a sufficient distance that ear 66 on end piece tion as shown in Fig. 3 will move can surface 65 will drop behind actuating projection 54 to a 72 downwardly permitting spring 67 to move ear position as shown in Fig. 5. As slide 25 moves S6 downwardly So end piece 65 is turned about forwardly, bolt 3 moves away from hammer 32 its pivot from the raised position shown in Fig. So the hammer may turn clockwise as viewed in 2 to an operative position as shown in Fig. 3. Fig. 5. Provided trigger 39 remains pulled, ham A notch i in rim 76 on the housing 58 provides ner Spring 35 Will cause the hammer 32 to move a detent retaining the Selector ever 3 in its Sear 34 rearwardly on Sear pin 37 until rear part forward or automatic position. 42 of the Sear 34 engages lip 43 on the trigger 39. 60 Then the hammer will be retained in cocked po At the forward portion of actuator bar 62 Sition. With the slide 25 in the position shown in there are provided Spaced abutments 8 and 82 Fig. 6, the bolt has been returned to battery po arranged to be respectively engaged by the for sition and a new shell has been inserted in the Ward and rearward ends of slide 25 upon re chamber as described in the above-mentioned ciprocation of the slide. Thus, when the gun is 65 Humeston patent. As the slide 25 continues to fired, slide 25 moves rearwardly until it engages move forwardly from the position shown in Fig. rear abutment 82 of the actuator bar 62, then 6, it engages forward abutment 81 and recipro actuator bar 62 is moved rearwardly until abut cates actuator bar 52 with its end piece 65 for ment 29 on the receiver arrests movement of the wardly so ear 66 engages behind actuating pro slide 25. During forward movement of the slide 70 jection 54 and turns sear tripper 52 clockwise, as 25 under the force of spring 27, its forward end viewed in Fig. 7. When the sear tripper 52 is thus engages abutment 8 and moves the actuator bar turned, its Sear engaging nose 55 depresses sear 52 forwardly until forward movement of the nose 45 to release the hammer to again fire the slide 25 is arrested by piston 26. Preferably, in Weapon. It will be noted that the sear tripper is termediate abutment 82 on the actuator bar 62 75 not actuated to release the hammer until the bolt 2,649,030 7 8 has returned to battery position. However, in automatically operated reciprocable slide movable mediately thereafter, slide 25 reciprocates actu from a battery position to a recoil position to ator bar 62 forwardly to repeat the firing cycle. cock the hammer following each discharge; a se In this way, the weapon will automatically fire as lective fire converter comprising a bracket on one long as the trigger 39 is pulled. When the trigger Side of the firearm adjacent the trigger and Sear, is released, sear tripper 52 is turned counter a Sear tripper pivoted on said bracket above the clockwise by spring 56 to the position shown in trigger engageable with and movable thereby, an Fig. 3 where actuating projection 54 is in its in actuator bar slidable relative to said bracket, a operative position so it will not be engaged by ear Stud connected to said bar and slidable in a slot 66 and firing of the Weapon Will cease. formed in Said bracket, an end piece pivotally With the selector lever in its forward position connected to Said Stud engaging and operating as just described, the weapon is fired automati Said Sear tripper upon reciprocation of said actu cally as long as the trigger is pulled. To convert ator bar, and a Selector on said bracket for shift from automatic to semi-automatic fire, it is Only ing Said end piece relative to said sear tripper. necessary for the marksman to move with the 3. In an automatic firearm having a hammer, thumb of his right hand, the selector lever 13 a Sear for retaining the hammer in cocked posi rearwardly from the position shown in Fig. 7 to tion, a trigger for disengaging the sear, and an the position shown in Fig. 8. As illustrated in automatically Operated reciprocable slide mov Fig. 12, with the selector lever 73 forward in its able from a battery position to a recoil position automatic position as illustrated in full lines, end 20 to cock the hammer following each discharge; a piece 35 and its ear S6 are lowered to their oper Selective fire converter comprising a bracket on ative positions. Movement of selector lever 3 one side of the firearm adjacent the trigger and to semi-automatic position, as shown in dotted Sear, a Sear tripper pivoted on Said bracket above lines in Fig. 12, causes can surface 72 to engage the trigger engageable with and movable there the underside Cf end piece 65 and turn it counter 25 by, an actuator bar slidable relative to said clockwise as viewed in Fig. 12, thereby raising the bracket reciprocated by the slide, an end piece end piece and its ear 66 to inoperative position, pivotally connected to said bar and having an as shown in dotted lines in Fig. 12. In its raised inwardly extending Sear tripper engaging pro inoperative position, ear 66 cannot engage actu jection, a tension Spring on said bracket yield atting projection 54 on the sear tripper. Hence, 30 ingly urging Said projection downwardly toward the gun will fire Semi-automatically in the same Said Sear tripper to operate Said tripper upon re fashion as the basic weapon. ciprocation of Said bar, and selector means for From the foregoing description it will be seen moving Said projection against the action of said that the Selective fire converter is a unitary con Spring. struction on a bracket with a housing which may 4. In an automatic firearm having a hammer, be readily attached to the Side of the weapon by a Sear for retaining the hammer in cocked posi a, new sear pin 3", a hammer bolt 38' substituted tion, a trigger for disengaging the sear, and an for the hammer pin 30, and a new transverse re automatically operated reciprocable slide movable ceiver bolt 32' substituted for the receiver pin 22. from a battery position to a recoil position to cock To install this converter it is not necessary to re 40 the hammer following each discharge; a selective place, or remachine, or in any way alter operat fire converter comprising a bracket on one side of ing parts of the gun. The converter is attached the firearm adjacent the trigger and sear, a sear to the side of the weapon and when attached se tripper pivoted on Said bracket above the trigger lectively provides either full automatic or semi engageable with and movable thereby, an actu automatic firing of the weapon. It is so simple ator bar slidable along said bracket reciprocated that it may be attached by a soldier in the field by the slide, an end piece pivotally connected to because he need only dismantle the trigger mech Said actuator bar and extending rearwardly of anism and re-assemble it with the new sear pin Said bracket, a tension spring on, said bracket and hammer bolt to attach the selective fire con yieldingly urging Said end piece toward said Sear verter alongside the trigger housing. Then, by a tripper, and a Selector can pivoted on said brack manipulation of his right thumb to shift the et engaging Said end piece to move it against the Selector 3 he may fire the gun either automati force of Said spring. cally or semi-automatically. 5. In an automatic firearm having a hammer, What is claimed is: a Sear for retaining the hammer in cocked posi 1. In an automatic firearm having a hammer, 5 5 tion, a trigger for disengaging the sear, and an a Sear for retaining the hammer in cocked posi automatically operated reciprocable slide mov tion, a trigger for disengaging the sear, and an able from a battery position to a recoil position automatically Operated reciprocable slide mov to cock the hammer following each discharge; a able from a battery position to a recoil position Selective fire converter comprising an actuator to cock the hammer following each discharge; a 60 bar slidable along one side of the firearm, means Selective fire converter comprising a bracket on Operated by the Slide for reciprocating said bar, a One side of the firearm adjacent the trigger and pivotally mounted Sear tripper having a sear en Sear, a Sear tripper pivoted on Said bracket above gaging portion for engaging the sear to disen the trigger engageable with and movable by the gage it from the hammer, an end piece pivotally trigger from an inoperative position to an opera 65 connected to Said bar, Said end piece being shift tive position, an actuator bar slidable on said able between an operative position for moving bracket reciprocated by said slide, an end piece said Sear tripper upon reciprocation of the side pivotally connected to said bar to engage and and an inoperative position displaced from said operate Said sear tripper, and a Selector can piv Sear tripper, means normally urging Said end oted on said bracket arranged to engage and 70 piece toward one of Said positions, and a selector shift said end piece to an inoperative position dis shiftable between an automatic position and a placed from said Sear tripper. Semi-automatic position, Said Selector being ar 2. In an automatic firearn having a hanner, ranged to move Said end piece against the action a sear for retaining the hammer in cocked posi of Said urging means. tion, a trigger for disengaging the Sear, and an 75 6. In an automatic firearm having a hammer, 2,649,030 O a Sear for retaining the hammer in cocked posi cock the hammer following each discharge; a tion, a trigger for engaging the Sear, and an au selective fire converter comprising a bracket on tomatically operated reciprocable slide movable one side of the fire arm adjacent the trigger and from a battery position to a recoil position to Sear, a guideway on Said bracket extending for cock the hammer following each discharge; a Se wardly thereof toward the slide, an actuator bar lective fire converter comprising a bracket on One reciprocated in Said guideway by the slide, a piv side of the firearm adjacent the trigger and Sear, otally mounted Sear tripper having a Sear engag an actuator bar slidable along Said. One Side of ing portion arranged to move the sear and re the firearm, means for reciprocating Said bar by lease it from the hammer, an end piece pivotally reciprocating movements of the slide, a pivotally 0. connected to Said bar and arranged to engage and mounted Sear tripper having a Sear engaging por move said Sear tripper, said end piece being tion for engaging the sear to release it from the shiftable between an operative position to engage hammer, an end piece pivotally connected to said said sear tripper and an inoperative position dis actuator bar, said end piece being shiftable be placed from said sear tripper, means normally tween an Operative position for moving said sear 5 urging Said end piece toward One of Said posi tripper upon reciprocation of the slide and an tions, and a Selector shiftable between an auto inoperative position displaced from Said Sear matic position and a Semi-automatic position, tripper, means normally urging said end piece to said selector being arranged to move said end Ward One of Said positions, and a selector mov piece against the action of Said urging means. ably mounted on said bracket and shiftable be 20 tween an automatic and a Semi-automatic posi ALONZO. F. GAIDOS. tion, Said Selector being arranged to shift said end piece against the action of Said means. References Cited in the file of this patent 7. In an automatic firearm having a hammer, UNITED STATES PATENTS a sear for retaining the hammer in cocked posi 25 Number Name Date tion, a trigger for disengaging the Sear, and an 2,462,130 Rudd ------Feb. 22, 1949 automatically operated reciprocable slide movable 2,465,487 Sampson et al. ------Mar. 29, 1949 from a battery position to a recoil position to 2,469,053 Roerner ------May 3, 1949