US2823589A

US2823589A - Selective fire converter and rate reducer

Info

Publication number: US2823589A
Application number: US279623A
Authority: US
Inventors: Alonzo F Gaidos
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-03-31
Filing date: 1952-03-31
Publication date: 1958-02-18
Anticipated expiration: 1975-02-18

Description

Feb.' 18, 1958 A. F. GAlDos SELECTIVE FIRE CONVERTER AND RAT; REDUCER 6 Sheets-Sheevt 1 Filed March 31, 1952 INVENTOR LQNZG F. SAB DGS BY @MWL 2Mb(- /AT'TORNEYS Feb. 18, 1958 A. F. GAlDos sELEcTlvE FIRE CONVERTER AND RATE REDUCER 6 Sheets-Sheet 2 Filed MaroR 31. 1952 INVENTOR Feb. 18, i958 A. F. @Amos sELEcTlvE FIRE CONVERTER AND RATE REDUCER Filed March 51, 1952 6 sheets-sheet :s

INVENT OR ATT RNEYS E Feb. S, 1958 A. F. GAlDos sELEcTrvE FIRE CONVERTER AND RATE REDUCER Filed March 3;, 1952 6 Sheets-Sheet 4 INVENTOR Hzo/vzaFQ/as TTORNEYS Feb. 18, 1958 A. F. @Amos SELECTIVE FIRE CONVERTER AND RATE REDUCER 6 Sheets-Sheet 5 Filed March 31, 1952 Fe '18, 1958 A. F. GAlDos sELEcTvE FIRE CONVERTER AND RATE REDUcER Filed March 51, 1952 /Z/\ Anda United States SELECTIVE FIRE CONVERTER AND RATE REDUCER This invention relates to automatic rearms and particularly concerns a cyclic rate reducer for automatic firearms of the type having a pivoted hammer cocked by a slide which is reciprocated upon expansion of gases from the explosion chamber causing automatic discharge of the firearm after the slide returns to its battery position.

Firearms currently employed by Armed Forces are generally of the semi-automatic type such as U. S. rifle cal. .30 M1 of the type shown in Garand Patent No. 2,377,338 and U. S. Carbine cal. .30 M1 of the type disclosed in Humeston Patent No. 2,308,283. In both weapons, explosion gases from the barrel or firing chamber of the gun reciprocate a slide which moves to and from a battery position to eject the used cartridge, cock the hammer, insert a fresh cartridge and then close the chamber upon return of the slide to its battery position. Normally, the hammer is retained in its cocked position by a sear which is released by operationof the trigger to initiate the firing cycle. Even though the trigger remains pulled, the sear engages the hammer to prevent a second firing cycle until the trigger is first released and then again pulled.

To fulfill a military requirement for an automatic weapon or a selectively automatic or semi-automatic weapon, various conversions, modifications and redesigns of these weapons have been proposed. In most of these, automatic operation is provided by causing release of the sear from the hammer upon return of the slide to its battery position for as many firing cycles as the trigger remains pulled. For example, the trigger is pulled, the weapon fires, the slide reciprocates to recock the hammer, then returns to battery position whereupon the sear is released from the hammer and the weapon is again fired, the cycle continuously repeating until the trigger is released. Examples of such selective tire converters for the U. S. carbine cal. .30 M1 are found in my copending applications Serial No. 780,214, filed October 16, 1947, now Patent No. 2,649,031, Serial No. 138,766, filed January 16, 1950, now Patent No. 2,649,030, and Serial No. 187,035, led September 27, 1950, now Patent No. 2,587,460.

In these modifications and conversions, the rate of fire is usually in excess of that required. For example, the Gaidos selective fire converter provides a rate of fire of about 750 rounds per minute for the U. S. Carbine cal. .30 Ml. All of these conversions and lmodifications provide about the same rate of automatic fire for reciprocating slide type weapons.

It has been determined by competent authority that this rate of fire should be reduced to avoid a waste of ammunition and avoid putting more than one shot in the same area of the target. A reduction of to 50% is considered desirable. In other words, a firing rate of about 300 rounds per minute is proposed for an automatic weapon of this type.

An important object of this invention is to provide an automatic firearm of the reciprocating slide type which arent 2,823,589 Patented Feb. 18, 1958 will fire at a reduced rate. More particularly, an object of the invention is to provide an automatic firearm of the reciprocating slide type with a rate reducer which will automatically effect discharge of the firearm a predetermined time following return of the slide to its battery position thereby increasing the period of each firing cycle and reducing the rate of fire. l

Another object of the invention is to provide a combined selective fire converter and cyclic rate reducer for semi-automatic firearms to effect selectively either semiautomatic or automatic operation of the weapon at a reduced rate.

In the attainment of these objects, an important feature of the invention resides in the arrangement of a cyclic rate reducer for automatically disengaging thesear from the hammer a predetermined time following return of the slide to its battery position. This cyclic rate reducer, in its preferred form, includes a plunger slidable in a guideway, the plunger being normally urged from aset position in a direction to Cause disengagement of the sear from the hammer. The plunger is then released by return of the slide to its battery position and a predetermined time later causes release of the sear to discharge the weapon.

In the form illustrated in this application, the plunger is moved, by reciprocating action of the slide, against thc action of the spring, to a set position where it is retained by a latch. Return of the slide to battery position actuates a latch release member which disengages the latch from the plunger leaving the plunger to the force of the spring. Then, the plunger leaves its set position and moves in a direction to operate the sear tripper for disengaging the sear from the hammer a predetermined time after the slide returns to battery position.

To provide selective, semi-automatic, or reduced rate full automatic operation, the sear tripper itself may be provided with a pivoted member movable by a manually operable selector cam to and from an operative position with respect to the sear. In another form of the invention, the latch release member has a pivoted pawl which is movable to and from an operative position with respect to the latch by a manual selector.

Both forms of the selective fire converter and cyclic rate reducer are compact units which may be easilyA assembled onto the standard U. S. rifle cal. .30 M1 with minor modification of existing parts and the U. S. Carbine Cal. .30 M1 without modification .of existing parts of the basic weapon. Thus, the soldier in the field may, lwith the present invention, convert a rie or a Carbine from a semi-automatic Weapon to one that is selectively either semi-automatic or reduced rate full automatic.

Other objects and features of the invention will become apparent from the following specification taken in connection with the accompanying drawings wherein- Fig. 1 is a partial side elevational view of a standard U. S. rifle cal. .30 Ml having attached thereto a selective re Converter and rate reducer embodying the present invention;

Fig. 2 is a similar view but with some parts broken away and others in section for purposes of clearness;

Fig. 3 is an enlarged view similar to Fig. l with the parts of the selective fire converter and rate reducer shown in detail;

Fig. 4 is a top plan view of lthe selective fire converter and rate reducer illustrated in Fig. l;

Fig. 5 is a similar view with some parts removed and others shown in section for purposes of clearness;

Fig. 6 is a vertical sectional view of the converter and rate reducer with the plunger shown latched in its set position;

Fig. 7 is an enlarged detail view of the action for the Y.30 M l to-,Which is applied a selective nre converter and ,rate-,reducer embodying another form of the invention;

VFigrll is a top plan view of the rifle and converter and rate reducer shown in Fig.

.-Fig. 12` is an enlarged top plan view of the selective -re converter and rate reducer shown in Figs. 10 and 11 with someparts `broken away and others shown in section for purposesV of clearness;

Fig. 13 is a phantom view as seen from the right hand side Vof the weapon showing the converter and rate resition; A g Fig. 14 is a similar view showing the slide in its retractedfposition;

Fig. 15 is a view like Fig. 11 but with the selector in .semi-automatic position; Y Fig. 16 is a partial side elevation showing the action of Ythe carbine and the arrangement of the sear tripper;

Fig'. 17 is an enlarged perspective view of the sear tripper used for the Carbine Fig. 18 s an enlarged perspective view of the latch release member forming a part of the selective fire conv verter .and rate reducer for the Carbine.

Fig. 19 is a transverse sectional view taken on the line 19-19 of Fig. 13;

Fig. 20 is a transverse sectional view taken on the line 20e-20.01 Fig. 13; and

Fig. 21 is a transverse sectional view taken on the line 21-21 of Fig. 13.

In its preferred form, the invention includes a housing secured to the firearm forming a guideway extending 10ngitudinally thereof in which slides a plunger, spring urged, from a set position in a direction to operate the sear tripperand release the sear from the hammer to discharge the weapon. Reciprocation of the slide moves the plunger againstthe action of the spring to its set position Where it is retained by a latch during return of the slide toits battery position. Upon its return to battery position, the slide operates a latch release member to disyengage the latch from the plunger and permit the plunger to move in a direction to operate the sear tripper. A manually operable selector mounted on the housing includesjacai'n movable to render the selective lire converter either operative or inoperative depending upon whetherfully automatic or semi-automatic operation is desired.

For Van illustration of the selective tire converter and rate reducer as applied to U. S. rie cal. .30 M1, reference may beV had to Figs. 1 to 9, inclusive, of the drawings. This rie has a stock 21 in which is supported barrel 22 extending forwardly from receiver 23. Discharge of a cartridge inthe tiring chamber at the receiver end of the barrel causes gases to expand in a pressure cylinder 24 and reciprocate slide or bolt 25. Cam surface 26 on the bolt engages hammer 27 to move the hammer about pivot Vducer set for automatic re and the slide in its battery po- Y 'its battery position, as shown in Fig/2, release of trigger 30 will release sear 35 and permit the hammer to move slightly forward until projection 31 is engaged by main sear 29. Hence, the weapon is normally intended for semi-automatic firing. After tiring the weapon once,i a subsequent cycle can be initiated only by releasing trigger 30 and again pullingit.` Hence, the trigger must be pulled for each shot red by the weapon.

To provide selectively automatic or semi-automatic re, and to provide automatic lire at a reduced rate, the selective tire converter and rate reducer of the present invention may, after slight modification of existing components, be attached to the U. S. rie cal. .3()` Ml;

As illustrated in Figs. 3-6', a housing 41 having aclosed outer side 42, a top 43 and a bottom 44 forms, with the sides of the weapon proper, a guideway of substantially rectangular cross-section extending longitudinally of the weapon. At its rear end, this housing 41 has a projecting Ylug 45 arranged to engage a recess normally present in the rear of the weapon. With the lug 45 engaged 'in such recess, the entire housing may be secured to the weaponby a single bolt 46 extending transversely through 'the housing 41 and threaded into its side.

y VSlidable longitudinally in the guideway formed by the pin 28. When the hammer reaches its cocked po- Y sition (Fig. 2), the bolt overrides the hammer. To retain'the hammer 27 in cocked position, a main sear 29 on tr1gger'30 engages abutment 31 on the hammer. When the trigger 30 is pulled, it releases sear 29 from abutment 31 thereby permitting hammer spring 32 to move hammer 27 about its pivot pin 28 and strike ring pin 33 to discharge the weapon. Assuming the trigger 30 remains pulled, subsequent reciprocation of slide 25 by gases from the firing chamber will move the hammer 27 to the position shown in Fig. 2 where abutment 34 will be engaged by pivotally mounted auxiliary sear 35 to retain the hammer in cocked position. After the bolt 25 returns to housing 41 is a plunger 47 of substantially rectangular cross-section and somewhat elongated. A guide rod 48 is threaded into a filler block 49 which may be secured in place atthe rearend of the housing 41.` Plunger- 47 is formed with a longitudinal bore 50 so it may slide along the rod 48. Surrounding rod 48 between plunger 47 and filler block 49 is a coil compression spring 51 normally urging Vthe plunger forwardly from a set position to a position for operating the sear tripper subsequentlyto be described. Plunger 47 has an upwardly extending' projection 52 arranged to engage one side of bolt handle l53 extending'ou'twardly from the bolt for manual manipulation of the bolt. Inasmuch as bolt handle 53`reciprocates with the'b'olt or slide 25, rearward movement of the slide will cause rearwardrmovement of kprojection 52 and its plunger 47 toward a set position at the rear of the guideway in the housing and against the action of spring 51. Arranged to slide along the inner part of the housing adjacent the Vside Aof the weapon is a sear tripper 54 having -at its rear end an inwardly offset portion 55 from which projects an abutment 56 to be engaged by the rear end 57 of the plunger 47 as it moves rearwardly to its set position. Pivotally connectedby a rivet 55 to the offset portion'SS of the seartripper is a scar tripper pawl 58 having a projection 59 extending inwardly toward the action of the weapon to reciprocate in a short path in the area of the auxiliary sear 35. As illustrated in Fig. 7, projection 59 may engage sear 35 to release it from the abutment 34 onjthe hammer 27. Thus, even though the trigger 33 remains pulled, the 'sear 35 will be released and the gun willcontinue toY fire. w g

Slidable along 'the inner surface ofy outer wall 420i the housing 41 is a latch-release member 61' having at its rear .endfan abutment 60 to be engaged by rear 7end 57 of the plunger 47 as the plunger moves to its set position. This rearward movement of latch release member 61f moves rearwardly latch'release cam 62 on'the bottom edge of member 61 so notch 63 in the lower edge of sear release 'member 61v overli/es opening 64 in bottom 44 of the housing therebyV permitting latch 65 to enter the hou'sing`nd`engage notch 66 formed in the bottom of plunger; 47. Latch 65 is pivoted by 'a pin 65 to an ear 67 depending from the outer side 42 `of the housing. Normally, latch 65.is urged by a spring 68 so it will enter the faperture'64 in the bottom ofthe housing. For this purpose, `spring"68` is arranged in a socket 69 in the latch` bodyfand engages the bottomrof the housing. /Wh'e'nplungfer 47 reaches its s et position, it moves slightly furtherfrearwardly to move ,the` abutment 60 and the latch release memberl rearwardly. Then,as slide handle' @in/invesV forwardly, plunger`47 is permitted-to 45 move forwardly until it is engaged and arrested by latch 65 which enters notch 66 in the plunger. This is .the set position of the plunger 47 where the plunger is retained until the latch is released.

As the slide continues its forward movement, it inserts a new cartridge into the tiring chamber. When it reaches its battery position, handle 53 engages an upwardly projecting lug 71 on the forward end of the latch release member 61 lthereby moving the latch release member forwardly so its cam surface 62 depresses the nose of latch 65 to disengage the latch from notch 66 in the plunger 47. Thus plunger 47 is released to the action of spring 51 which forces the plunger to slide forwardly in ythe guideway until it engages abutment 72 on the forward end of sear tripper 54. This forward movement of the sear tripper moves projection 59 forwardly to engage the auxiliary sear 34 and depress auxiliary sear 34 to disengage it from the hammer thereby again discharging the firearm.

Near the rear of the inner side of the top 43 of housing 41 a flange 74 extends upwardly and is provided with a longitudinally extending slot 75. Extending through this slot 75 is a rivet 76 secured to 'a selector 77 to slidably support the selector with respect to the housing 41. Selector 77 has a knurled knob 78 which is accessible to the thumb of the marksman for sliding the selector forwardly or rearwardly. Depending from the forward part of the selector is a `cam 79 disposed to move in a path for engagement with projection 59 on the sear tripper and depress it against the action of spring 81 extending rearwardly from the main body 54 of the sear tripper and acting upon the pawl 58 'to move the sear tripper projection 59 toward an inoperative position. When selector 77 is moved forwardly so rivet 76 is in the forward end of slot 75, cam 79 engages and depresses projection 59 so it will disengage auxiliary sear 35 from the hammer when the sear tripper 54 is moved forwardly by engagement of plunger 47 with abutment '72. Thus, the forward position of selector 77, as viewed in Fig. 2, is the automatic position whereas rearward position of the selector 77 as viewed in Fig. l is the semi-automatic position. A detent spring 83 is secured to the underside of the selector 77 to engage hole 84 in the top of the housing when the selector is in semi-automatic position and to engage hole S in the top of the housing when the selector is in automatic position.

Assuming the selector '77 is forward in its automatic` position as viewed in Fig. 2, discharge of the firearm by pulling trigger 30 and releasing hammer 27 will cause operation of the slide or bolt 25 and reciprocate the handle 53 rearwardly. This rearward movement of handle 53 by engagement with projection 52 retracts plunger 47 rearwardly against the action of spring 51. As the plunger 47 is moved rearwardly by slide handle 53, it engages abutment 68 on the latch release member 61 and abutment 56 `on the sear tripper 54 moving these two sliding parts rearwardly with respect to 'the housing. When the slide handle 53 begins its forward movement, plunger 47 moves forwardly slightly until it is engaged by entry of latch 65 into notch 66. Rearward movement of latch release member 61 moves latch release cam 62 rearwardly with respect to opening 64 in the bottom of the housing thereby permitting free entry of the latch 65 into the housing. Rearward movement of the sear tripper 54 moves the sear tripper projection 59 rearwardly of auxiliary sear 35 thereby permitting 'the sear to retain the hammer in its cocked position.

Assuming the trigger 30 remains pulled, the hammer 27 will be retained in cocked position by engagement of auxiliary sear 35 with notch 34 on the hammer. With the plunger retained in its set position by latch 65, slide handle 53 moves forwardly with the slide until the slide approaches its battery position. Then, handle 53 engages projection 71 on the forward end of latch release member 61 thereby moving the latch release 6 member 61 forwardly just as the slide reaches its battery position. This forward movement of latch release member 61 moves latch release cam 62 forwardly to depress latch 65 and disengage it from notch 66 n the plunger thereby releasing the plunger 47 to the action of spring 51 so that plunger is moved forwardly along its guide rod 48. After the plunger has traveled the full length of the guideway formed by the housing 41, it engages abutment 72 on the forwardmost end of `sear tripper 54 thereby moving the entire sear tripper forwardly. As selector 77 is in its forward automatic position, sear tripper projection 59 is retained in its lower position against the action of spring 81 by engagement with cam 79 on the lower part of the selector 77, auxiliary sear 35 is depressed thereby releasing it from abutment 34 on hammer 27 so lthe hammer is moved by its spring to discharge the cartridge in the chamber.

In the past, automatic operation of weapons of this type has been accomplished by causing release of the sear immediately when the slide reaches its battery position. In accordance with the present invention, the time required for the plunger 47 to travel the length of housing 41 adds to the period of each firing cycle. Hence, the time elapsed between the return of the slide to battery posi-tion, until the plunger 47 engages and moves abutment 72, is added to the time required to fire each single round in the weapon. Thus, the rate of lire of the weapon is accordingly reduced.

With the arrangement described the tiring cycle is reduced by about 25%. If a greater reduction is required, the travel of the plunger can be increased, the compression force of the spring decreased, or a series of plungers may be utilized, each releasing the latch of the next plunger.

In the event it is desired to use the rifle as a semiautomatic weapon, it is only necessary to move selector 77 rearwardly by shifting the knob78 with the thumb. Then, selector cam 7 9 is moved rearwardly with respect to sear tripper projection 59 which is raised by spring 81 to a position where it will not engage auxiliary sear 35. With the selector in this semi-automatic position, firing of the weapon causes rearward movement of the slide which in turn moves the plunger 47 to its set position where itis engaged by latch 65. Forward movement of the slide causes handle 53 to engage projection 71 and operate latch release member 61 to disengage latch 65 from the notch 66 permitting forward movement of plunger 47. Engagement of abutment 52 by plunger 47 when it reaches its foremost position again operates sear tripper 54. However, as the spring 81 moves sear tripper projection 59 to inoperative position, because selector 77 is in semiautomatic position, the forward movement of the sear tripper does not release the auxiliary sear 35. In order to tire the weapon it is necessary to release the trigger 33 thereby releasing auxiliary sear 35 and permitting the hammer to move slightly until it is engaged by main sear 29. Then, pulling of the trigger 33 will again fire the weapon.

In all weapons of the reciprocating slide type a similar arrangement may be employed to reduce the rate of fire when the weapon is used as an automatic weapon. As an example of another application of this preferred form of the invention reference may be had to Figs. 8 to 17 inclusive which disclose the invention as applied to U. S. Carbine cal. .30 Ml. This Carbine is also reciprocating slide type but the trigger action and sear arrangement differ somewhat as compared to the U. S. rifle cal. .30 M l heretofore described.

Several arrangements have been proposed for converting the U. S. carbine cal. .30 M1 from a semi-automatic weapon to a selective semi-automatic or automatic weapon. Of the several developments for this purpose, the most satisfactory are disclosed in my aforementioned copending applications Ser. Nos. 780,214 filed October 16, 1947, 138,766 filed January 16, 1950, and 187,035 led September 27, 1950. In all of these, the sear is released to retain the hammer in its cocked position.

inmediately after-*the slide reachesV its battery position.

the drawings and about to be described is designed to reduce the rate of fire from 750 rounds per minute to the range of 300 to 500 rounds per minute.

This weapon has a receiver 100 in the forward end of which a barrel 101 is threaded. Locked by dovetail joint 102 at the rear of the receiver and a transverse bolt 103 vat the forward end of the receiver is a trigger housing 104 arrangedbelow the receiver. Pivotally supported on a hammer pin 105 extending across the trigger housing is a hammer 106 which moves in an arcuate path between a cocked position and a firing position. For the purpose of retaining the hammer 106 in a cocked position a sear 107 is pivotally mounted on a s ear pin 108 extending across the trigger housing. Also pivoted on sear pin 108 is a trigger 109 which has a lip 111 extending upwardly from its rear portion. Interposed between this lip 111 and a depending shoulder 112 on the sear 107 is a spring 113 .arranged in a socket in the trigger. Sear 107 is provided with a longitudinally elongated slot by which the sear is mounted on sear pin 108 to permit pivotal movement of the scar about Vthesear pin and also to permit longitudinal movement of the sear in the trigger housing with respect to the sear pin.

Forwardly extending nose 119 on the sear 107 is arranged to engage an abutment 114 on the hammer 106 When cocked, the force of hammer spring 115 on the hammer acts through the sear 107 to overcome spring 113 and move the sear rearwardly with respect to the sear pin 108 so the rearwardly extending portion 118 of the sear overlies upwardly extending lip 111 on the trigger.

tending portion 118 to cause pivotal movement of the sear about the scar pin 108 and disengage the nose 119 from the hammer. After the Weapon is discharged, the hammer is recocked Vby rearward movement of bolt 116 which is effected by expansion of gases to operate a piston 117 and thereby reciprocate slide 120. Nose 119 on the sear reengages the hammer and the sear is moved rearwardly against the lip 111. Hence, the sear reengages the hammer and retains it in cocked position even though the trigger remains in pulled position. In order to again discharge the weapon it is necessary to release the trigger so the sear is moved rearwardly by the force of the hammer spring until the rearwardly extending portion 118 again overlies the lip 111.

For the purpose of providing selectively either automatic or semi-automatic operation, a sear tripper 121 is mounted on the hammer pin 105. This seartripper is provided with a pair of depending supporting

arms

122 and 123 having holes such as 124 for engaging the hammer pin 105 on opposite sides of the hammer. depending

arms

122 and 123 may be connected by a cross member 125. Extending rearwardly from the sear tripper 121 is a sear engaging arm 126 having a foot portiony 127 arranged to overlie step shoulder 128 on the sear 107. When the trigger is pulled and in the position shown in Fig. 16 with the sear held forwardly by engagement with lip 111, sear engaging foot 127 on the sear tripper 121 overlies the raised portion of step shoulder 128. Hence, movement of the sear tripper in a clockwise direction as shown in Fig. 16 will depress the nose of the sear disengaging it from the hammer. However, when the trigger is released and the sear is moved rearwardly so rear portion 118 overlies the lip 111, then raised portion of step shoulder 128 is moved rearwardly of the sear engaging foot 127 so limited clockwise movement of the scar tripper will not disengage the Sear from the hammer. Hence, the sear tripper is operative for the purpose of causing counter clockwise movement of the Sear at a certain time in a manner to be explained. The main When l the trigger is pulled, lip 111 engages the rearwardly ex- The two ,r portion ofI a sear tripperV 121 has extending from its side an abutment pin 131.

In addition to the insertion of the sear tripper in the trigger housing, the selective fire convertor and rate reducer for U. S. carbine cal. .30 Ml includes a housing 132 having an outer side 133, a top 134, a bottom shoulder 135 from`which there extends a depending ange 136. At its rear end, housing 132 has an inwardly extending lug 137 arranged to enter the dovetail joint 102 to retain the rear end of the housing in position. In addition, the housing is secured to the side of the carbine by bolt 103 which is threaded into tapped hole 139 in bracket 140 on the bottom of the ange 136. When properly positioned and secured by the bolt 103, the top, the outer side, and the bottom yof the housing, together with the exposed side of the weapon, form a guideway of substantially rectangular cross-section in whichI slides a plunger 141. Plunger 141 is provided with a longitudinally extending bore surrounding guide rod 142 which has one end secured in end wall 143 at the rear of the housing. Interposed between end wall 143 and the rear end 144 of the plunger 141 is a coil compression spring surrounding the guide rod 142. This spring normally urges the plunger from a set position as shown in Fig. 14 forwardly in a direction to cause disengagement of the sear in a manner to be described.

Also slidable in the guideway ofthe housing is rectangular body portion 145 of actuator bar 146 having at its forward ends spaced

abutments

147 and 148 arranged to engage the back 149 and front 151 respectively of slide 120. Body'portion 145 of actuator bar 146l is provided with a longitudinal bore 152 guiding it along guide rod 142. As thel body portion 145 snugly tits the walls of the guideway, it also provides a support for the forward end portion of the guide rod. Along the lower part of its inner face actuator bar 146 is provided with an undercut portion 153 having front and rear abutments 154 and 155 respectively for a purpose to be described.

After the weapon is discharged and the explosion gases move slide 120 rearwardly by acting on piston 117, the rear end 149 of slide 120 by engaging abutment 147 on the actuator bar 146 moves the actuator bar rearwardly in the housing. This rearward movement of the actuator bar 146 causes rearward movement of plunger 141 to a set position as shown in Fig. 12. Pivoted on flange 136 by a rivet 157 is a latch 158' having at its rear end a nose 159 resiliently urged by leaf spring 159 to engage notch 161 in the plunger 141. On the bottom of its forward end, latch 158 has a cam surface 162 by which the latch is disengaged from the plunger in a manner to be described.

On the inner surface of iiange 136 there is supported for limited sliding movement a latch release member 163 having a pair of

elongated slots

164 and 165 through which extend rivets 166' and 167 respectively to permit sliding movement of the latch release member 163. These rivets are secured in the depending flange 136 of the housing. At its forward end, latch release member 163 has an upwardly extending projection or abutment 168 positioned in the undercut recess 153 of the actuator bar 146 to be alternately engaged by the front and rear abutments 154 and 155 as the actuator bar is reciprocated by the slide. At the rear end of the latch release member 163 an extension 169 is secured by pivot 170. Latch release extension 169 has an inwardly projecting cam 171 arranged to engage depending nose 162 on the latch 158. Abutments 154 and 155 are so spaced on the actuator bar 146 that during rearward movement of the actuator bar by reciprocation of the slide 118` the forward abutment 154 engages projection 168 and moves the latch release member 163 rearwardly a distance just suicient to move cam 171 from beneath nose 162 on the latch. Then, when the slide 120 moves forwardly, rear abutment on the actuator bar engages projection 168 just as the slidereturns toits battery position. This 'of spring 181.

moves the latch release member 163 and cam 171 forwardly beneath the cam surface 162 on the latch 158 thereby rotating the latch about the pin 157 to remove nose 159 from notch 161 on the plunger. In this manner, plunger 141 is released to the force of spring 150 just as the slide returns to battery position.

Mounted on rivet 166 for pivotal movement about the axis thereof is a sear tripper lever 172 having a forwardly projecting arm 172 with an upwardly extending cam surface 173 arranged to be engaged by the plunger 141. Lever 172 has a depending arm 174- positioned to engage projection 131 on the sear tripper 121 for the purpose of operating the sear tripper. A wire spring (not shown) surrounding hammer pin 105 and arranged to engage the sear tripper and the trigger housing to normally urge the Sear tripper in a counter-clockwise direction as viewed in Figs. and 16 resiliently urges projection 131 against depending portion 174 of the sear tripper lever 172 thereby positioning the sear tripper lever so cam surface 173 is disposed in the path of the plunger 141 as best illustrated in Fig. 14.

When plunger 141 is released from latch 158' it is moved by spring 150 forwardly toward the front of the housing. During this forward movement, front end 179 of the plunger 141 rides over cam surface 173 of the sear tripper lever 171 thereby depressing the sear tripper lever so it moves projection 131 and sear tripper 121 to disengage the sear 167 from the hammer, provided the trigger remains pulled so the sear tripper foot 127 will engage the raised shoulder 12S of the step on the sear 107.

For the purpose of providing selective automatic or semi-automatic operation., the pivoted extension 169 of the latch release member is normally urged by leaf spring 181 in a direction so cam 171 is moved away from cam surface 162 on the latch 158. Thus, as illustrated in Fig. the cam 171 is urged by spring 181 to a point disposed below the cam surface 162 of the latch 15S so the latch is not released when the latch release member 163 is moved forwardly by forward movement of the actuator bar 146. To force the cam 171 against the action of spring 181 and to provide automatic operation at a reduced rate, a selector 182 having a thumb operable knob 183 is pivoted by the pin 157 on the ange 136 of the housing. Selector 182 has a camming projection 185 extending inwardly below the latch release member extension 169 and arranged to engage the eX- tension so movement of the selector to the position shown in Figs. 13 and 14 moves the cam projection 185 in a manner to raise the release member 171 against the action As the latch release member slides forwardly, the cam 171 will move in a path arranged to engage the cam surface 162 on the latch 158v thereby releasing the latch from the plunger 141. Extending from the lug 137 forwardly beneath the selector 182 is a detent spring 186 arranged to retain the selector in either the automatic or semi-automatic position. For this purpose, the spring has a raised detent portion 186 over which the camming projection 185 rides.

When the selector 182 is in semi-automatic position as shown in Fig. l5, the weapon will fire a single shot for e'ach operation of the trigger. rThus, when the trigger is pulled, it releases the sear from the hammer which discharges the weapon and causes reciprocation of the slide 126. This moves the actuator bar 146 rearwardly to move the plunger 141 rearwardly into engagement with the latch 158. Forward movement of the s-lide moves the actuator bar forwardly so the latch release member 163 is moved forwardly.V However, as spring 181 urges the extension member and cam 171 downwardly, and cam projection 185 on the selector perm-its such downward movement, the cam 171 does not engage cam surface 162 on the latch so that latch remains engaged with the plunger. When the slide reaches its battery position the hammer is retained in cocked position by the sear which engages the lip 111 on the pulled trigger. Thus,

10 the trigger must be released and again pulled in order to fire the weapon.

When the selector 182 is moved to automatic position as illustrated in Figs. 14 and 13, operation of the trigger discharges the weapon and causes reciprocation of the slide 120. Rear end 149. of the slide engages abutment 147 on the actuator bar 146 moving the actuator bar rearwardly to force the plunger 141 against the action of spring 150 until the plunger is engaged by nose 159 on latch 158. Thus, the plunger is retained in set position as the slide 118 on the actuator bar moves forwardly during completion of the reciprocation of the slide. As the slide approaches its battery position, rear abutment on the actuator bar engages projection 168 on the latch release member 163 to move the latch release member forwardly. Inasmuch as the position of the selector is such that cam projection retains the latch release cam 171 in position to engage'cam surface 162 on the latch, this forward movement of the latch release member 163 will cause the cam 161 to move the latch and release it from the plunger. Then, the force of the spring 156 moves the plunger 141 forwardly so its front end 179 engages the raised cam portion 173 on the sear tripper lever 172 to depress the sear tripper lever and cause it to rotate about its pivot pin 166. This rotation of the sear tripper lever causes arm 174 to move projection 131 and sear tripper 121 about the hammer pin so sear tripper foot 127 depresses the raised step 128 on the sear and releases the sear from the hammer. Hence, the weapon is automatically fired and the cycle, completion of which has been delayed by the travel time of the plunger 141, is repeated as long as the trigger is held in its pulled position. Release of the trigger permits the sear to move rearwardly so it is not engaged by lip 111 on the trigger. As a result, the raised step 128 is moved` out of the path of movement of the foot 127 on the sear tripper. Thus, when the trigger is released the sear tripper is no longer operative to release the sear and the ring of the weapon ceases.

In the various selective tire converters for U. S. carbine cal. .30 M1 the sear tripper has been operated at the instant the slide reaches its battery position thereby repeating the ring icycle at the rate of about 750 rounds per minute. In the present instance, each firing cycle has an increased period due to the time required for plunger 141 to move from its set position to the point where it engages and moves the sear tripper lever. In this way the slide operates the rate reducer which after a predetermined time operates the sear tripper to release the scar and repeat the firing cycle. The addition of this predetermined time to the period of the tiring cycle reduces the rate of re of the weapon in automatic operation from about 750 rounds per minute to the range of 300 to 500 rounds per minute. Should a further reduction be desired the length of the movement of the plunger may be increased, the length of the spring reduced, or a series of plungers may be used.

While the embodiments of the invention disclosed io. this application are illustrated as applied to a semi-aut':A matic weapon for converting the weapon to a selective automatic or semi-automatic and providing a reduced rate of lire for automatic operation, it will be apparent that the rate reducing features of the invention may be corporated in a fully automatic weapon without departing from the intended scope of the invention. These einA bodiments are intended for illustrative purposes and. should not be construed as limiting the scope of the invention as dened by the appended claims.

What I claim is:

1. An automatic firearm comprising an automatically reciprocating slide, a hammer cocked by rearward m-ove` ment of said slide, a sear engageable with said hammer to retain it in cocked position, rate reducer means moved -along a path to set position by rearward movement of said slide, a latch at the rearwardend of said path for retaining said rate reducer means in said set position during forward movement of said slide and released as said slide approaches its battery position, and sear tripper means operated by forward movement of said rate rcducer means at the forward end of said path a predetermined time after release of said latch for disengaging said sear from said hammer to discharge the firearm.

2. An automatic firearm comprising an automatically reciprocating slide, a hammer cocked by rearward movement of said slide, a sear engageable with said hammer to retain it in cocked position, sear tripper means for disengaging said sear from'said hammer to discharge the firearm, rate reducing means for operating said sear tripper, spring means normally urging said rate reducing means in a forward direction to operate said sear tripper, and a latch for retaining said rate reducing means in set position against the force exerted by said spring means during forward movement of said slide, said latch being released as said slide approaches its battery position whereby said rate reducing means operates said sear tripper to discharge the firearm a predetermined time after release of said latch.

3. 1n an automatic firearm having an automatically reciprocating slide, a hammer cocked by rearward movement of said slide, and a sear engageable with said hammer to retain it in cocked position, a cyclic rate reducer comprising a plunger moved by rearward movement of said slide to a set position and normally urged from said set position in a forward direction to cause disengagement of said sear from said hammer, and a latch for retaining said plunger in said set position during forward movement of said slide, said latch being released as said slide approaches its battery position thereby causing disengagement of said sear and discharge of the firearm a predetermined time following release of said latch.

4. In an automatic firearm having an automatically reciprocating slide, va hammer -cocked by rearward movement of said slide, and a sear engageable with said hammer to retain it in cocked position, a cyclic rate reducer comprising a housing for mounting on the firearm, a plunger slidable in said housing normally urged from a set position in a direction to cause disengagement of said sear from said hammer, a latch carried by said housing for retaining said plunger in said set position during 'forward movement of said slide, and means operated by movement of said slide toward its battery position for releasing said latch whereby said plunger causes release of said sear a predetermined time following release of said latch.

5. In an automatic firearm having an automatically reciprocating slide, a hammer cocked by rearward movement of said slide, and a sear engageable with said hammer to retain it in cocked position, a cyclic rate reducer comprising a housing for mounting on the firearm, a plunger slidable in said housing and normally urged from a set position in a direction to cause disengagement of said sear from said hammer, a latch carried by said housing for retaining said plunger in set position during forward movement of said slide, a latch release member slidable in said housing and moved in a direction to release said latch by movement of said slide toward its battery position whereby said plunger is released to cause disengagement of said sear and discharge of the firearm a predetermined time after release of said latch.

6. In an automatic firearm having an automatically reciprocating slide, a hammer cocked by rearward movement of said slide, and a sear engageable with said hammer to retain it in cocked position, a cyclic rate reducer comprising a housing for mounting on the firearm, a plunger slidable in said housing, sear tripping means carried by said housing and operated by movement of said plunger from a set position, springmeans normally urging said plunger from said set position in a direction to operate said sear tripping means, and a latch carried by said housing for engaging said plunger to retain it in set position during forward movement of said slide, said latch 12 Ybeing released by movement of said slide toward its battery position to operate said sear tripping means and disengage said sear from said hammer to discharge the firearm a predetermined time following release of said latch.

7. In an automatic firearm having an automatically reciprocating slide, a hammer cocked by rearward movement of said slide, and a sear engageable with said hammer to retain it in cocked position, a cyclic rate reducer comprising a housing for mounting on the firearm, a plunger slidable in said housing normally urged from a set position in a direction to cause disengagement of said sear from said hammer, a latch on said housing for engaging said plunger to retain it in set position during forward movement of said slide, said latch being released by movement of said slide toward its battery position to cause disengagement of said sear and discharge of the rearm a predetermined time following release of said latch, and selector means having a manually operable lever on said housing for rendering said rate reducer operative and inoperative.

8. In an automatic firearm having an automatically reciprocating slide, a hammer cocked by rearward movement of said slide, and a sear engageable with said hammer to retain it in cocked position, a cyclic rate reducer comprising a housing for mounting on one side of the firearm to form a longitudinally extending guideway with the side of the firearm, a plunger slidable in said housing, sear tripper means carried by said housing, spring means normally urging said plunger from a set position at the rear of said housing in a forward direction to engage and operate said sear tripper means to cause disengagement of the sear from the hammer, a latch carried by said housing and engageable with said plunger to retain it in set position during forward movement of said slide, a latch release member slidable in said housing operated by movement of said slide toward its battery position for causing disengagement of the latch to allow said spring means to move said plunger forward to operate the sear tripper means and discharge the firearm a predetermined time following release of the latch, and selector means carried by the housing having a manually operable member for rendering said rate reducer operative and inoperative.

9. An automatic firearm comprising an automatically reciprocating slide, a hammer cocked by rearward movement of said slide, a sear engageable with said hammer to retain it in cocked position, a housing on the firearm, a plunger slidable in said housing resiliently urged from a set position toward a position to release said sear, an actuator bar slidable i'n said housing by reciprocation of said slide for moving said plunger to a set position, a latch for engaging said plunger and retaining it in set position during forward movement of said slide, said latch being releasable -by movement of said actuator bar during movement of said slide toward its battery position whereby said plunger releases said sear to discharge the firearm a predetermined time following release of sai'd latch.

l0. An automatic firearm comprising an automatically reciprocating slide, a hammer -cocked by reciprocating of said slide, ya sear engageable with said hammer to retain it i'n/cocked position, a housing on the firearm, an actuator bar slidable in said housing by reciprocation of said slide, a plunger moved to a set position by said actuator bar upon rearward movement of said slide, a sear tripper for disengaging said sear from said hammer, spring means normally urging said plunger from its set position in a direction to operate said sear tripper, and a latch for retaining said plunger in its set position during forward movement Vof said slide, said latch being released by said actuator bar during movement of said slide toward its battery position.

1l.n An automatic firearm comprising Ian automatically reciprocating slide, a hammer cocked by rearward movement of said slide, a sear engageable with said hammer to retain it in its cocked position, a housing on the firearm, a plunger slidable in said housing, an actuator bar slidable in said housing by reciprocation of said slide for moving said plunger to a set position, a sear tripper for disengaging said sear from the hammer, spring means normally urging said plunger forwardly from its set position in a direction to engage and operate said sear tripper, a latch release member moved in said housing by reciprocation of said actuator bar, and a latch for engaging and retaining said plunger in set position during forward movement of said slide, said latch being releasable by movement of said latch release member -upon reciprocation of said actuator bar by movement of said slide toward its battery position thereby operating said sear tripper to ydischarge the firearm a predetermined time following release of said latch.

12. An automatic firearm comprising an automatically reciprocating slide, -a hammer cocked by rearward movement of said slide, a sear engageable with said hammer to retain it in cocked position, a housing on said firearm, a plunger slidable in said housing, an actuator bar slida- -ble in said housing for moving said plunger to a set position, a sear tripper for disengaging said sear from said hammer, spring means normally urging said plunger in a direction to operate said sear tripper, a latch engageable with said plunger for retaining it in set position during forward movement of said slide, a release member slidable in said housing for engaging said latch to disengage it from said plunger, and a manually shiftable selector for selectively rendering said release member operative or inoperative, said release member, when operative, being moved to release said latch by reciprocation of said actuator bar during movement of said slide toward its battery position.

13. In an automatic firearm having an automatically reciprocating slide, a hammer cocked by rearward movement of said slide, |and a sear engageable with said hammer to retain it in its cocked position, a cyclic rate reducer comprising a housing forming a guideway extending longitudinally of the firearm, an actuator `bar reciprocated in said guideway by said slide, a plunger slidable in said guideway and moved to a set position by rearward movement of said actuator bar, a sear tripper lever pivoted on said housing for causing disengagement of the sear from the hammer, spring means normally urging said plunger from its set position toward said sear tripper lever, a latch on said housing for engaging said plunger to retain it in set position during forward movement of said slide, and a latch release member slidable in said guideway by movement of said actuator -bar during reciprocation of said slide toward its battery position for disengaging said llatch from said plunger thereby causing operation of said sear tripper lever to discharge the firearm a predetermined time following release of said latch.

14. In an automatic firearm having an automatically reciprocating slide, a hammer cocked by reciprocation of said slide, and a sear engageable with said hammer to retain it in its cocked position, a cyclic rate reducer comprising a housing forming a guideway extending longitudinally of the firearm, an actuator bar slidable in said guideway by reciprocation of said slide, a plunger slidable in said guideway and moved to a set position by reciprocation of said actuator bar, a sear tripper lever mounted on said housing for causing disengagement of the sear tripper Vfrom the hammer, spring means normally urging said plunger from its set position toward said sear tripper lever, a latch on said housing for engaging said plunger to retain it in set position, a latch release member slidable along said housing, a pawl pivoted on said latch release member for engaging said latch, and a selector having a cam surface engageable with said pawl to move it to and from an operative position With respect to said latch, said latch release member being moved to release the -latch by movement of said actuator barl during movement of said slide toward its battery position thereby discharging the firearm a predetermined time `following release of-said latch.

l5. An automatic firearm comprising an automatically reciprocating slide, a hammer cocked by rearward movement of said slide, a sear engageable with said hammer to retain it in its cocked position, a guideway, a plunger slidable in said guideway yand moved to a set position by rear-ward movement of said slide, a sear tripper slidable along said guideway and having an abutment engageable by said plunger for operating said sear tripper to release the sear to discharge the firearm, spring means normally urging said plunger from its set position 'in a forward direction toward the abutment on said sear tripper, and a latch for engaging said plunger to retain it in set position against the force of said spring during forward movement of said slide, said latch being released as said slide approaches its battery position whereby said plunger operates said sear tripper to discharge the firearm a predetermined time following the release of said latch.

16. An `automatic firearm comprising an automatically reciprocating slide, a hammer cocked by rearward movement of said slide, a sear engageable with said hammer to retain it in cocked position, a guideway on the firearm, a plunger slidable in said guideway moved to a set position by rearward movement of said slide, a sear tripper slidable along said guideway for releasing the sear from the hammer to discharge the firearm, an abutment on said sear tripper engageable by said plunger for releasing the sear from the hammer, spring means normally urging said plunger from its set position in a forward direction toward said abutment, a latch for engaging said plunger to retain it in set position against the force of said spring during forward movement of said slide, release means operated as said slide approaches its battery position for releasing said latch, said sear tripper having a pivoted pawl for engaging the sear to disengage it from the hammer, and a selector on said guideway for moving said pawl to and from an -operative position with respect to said sear.

17. In an automatic firearm having an automatically reciprocating slide, a hammer cocked by rearward movement of said slide, and a sear engageable with said hammer to retain it in cocked position, a cyclic rate reducer comprising a housing extending longitudinally of the firearm and forming a guideway, a plunger slidable in said housing and moved to a set position by rearward movement of said slide, a slidable sear tripper in said housing having an abutment engageable by said plunger, spring means normally urging said plunger from its set position in a forward direction toward said abutment to operate said sear tripper for releasing said sear from the hammer to discharge the firearm, a latch on said housing for engaging said plunger to retain it in said set position during forward movement of said slide, and a latch release member slidable along said housing for disengaging said latch, said latch release member being moved to disengage the latch as said slide approaches its battery position, thereby releasing said plunger to operate the sear tripper and discharge the firearm a predetermined time -following release of the latch.

18. In an automatic firearm having an automatically reciprocating slide, a hammer cocked by rearward movement of said slide, and a sear engageable with said hammer to retain it in cocked position, a cyclic rate reducer comprising a housing forming 'a guideway extending longitudinally ofthe firearm, a plunger slidable in said housing, a sear tripper slidable along said housing and having an abutment engageable by said plunger for operating the sear tripper to release the sear from the hammer to discharge the firearm, spring means normally urging said plunger from its set position in a forward direction toward said abutment, a latch for retaining said plunger 15 in said set position during forward movement of said slide, -a release member slidable along said guideway for releasing said latch for said plunger, said release member being operated to release the latch as said slide approaches its battery position, a pawlA pivoted on said sear tripper for engaging the Sear, and a selector on the operative position with respect to said sear.

References `Cited in the le of this patent UNITED STATES PATENTS Williams Feb. 15, 1949 Sefried Mar. 15, 1949 Sampson et a1 Mar. 29, 1949 Roemer May 3, 1949 VSe'fried Aug. 16,1949

Swidlo July 29, 1952