US2509530A - Machine gun fire retarder - Google Patents

Description

May 30, 1950 o. E. RosENGREN E1-AL 2,50%530 MACHINE GUN FIRE RETARDER 2 sheets-511.99% 1 Filed Aug. 3l, 1945 o. E. Rosl-:NGREN E'rAl. 2,509,530

MACHINE GUN FIRE RETARDER May 3o, 195o 2 Sheets-Sheet 2 Filed Aug. 5l, 1945 Gm, nu QN mm2 mm mmm. mM mm Patented May 30, 1950 MACHINE GUN FIRE RETARDER Ovar E. Rosengfen, Hamden, and Oswald 0. Sunderland, Fairfield, Conn.

12 Claims.

The invention relates to means for controlling the rate of re in machine guns; which has been found of importance incident to the use of such guns for both aerial and ground targets. For antiaircraft re and for sweeping fire from aircraft against enemy troops', a high rate of fire is desirable in order to reduce the angular interval between successive projectiles. On the other hand, in firing from xed emplacements or slowly-moving vehicles against ground targets a much slower angular movement ofthe gun and its rate of fire are frequently desirable. Also, with sweeping fire from the ground at grouped personnel, the total sweep for a burst will in many instances be only a few degrees, and it is sometimes desirable to hold the gun on individual is especially important because" of the comparatvely small supply which can be gotten to exposed positions in rough terrain. To minimize a waste of ammunition, as well as because gunners sometimes freeze on the trigger, and also to enable single shots to be red without stopping the complete automatic action, it is the purpose of the invention to afford means, eas-ily and quickly adjustable, to vary the rate of automatic nre, and which may be changed to semiautomatic; which may be embodied in a form practicable in current forms of automatic weapons with a minimum of change in construction, and without impairing the effectiveness of the weapon from all material standpoints. Among other features may be mentioned: a minimum of weight; simplicity and small number of parts; adaptability to manual dissassembly and reassembly; freedom from excessive wear incident to condi'- tions of eld service; low cost of manufacture and ease of replacement.

It is especially an object to enable the control device to be contained in the trigger housing, and to utilize and control the function of the action slide and buffer disc assembly heretofore employed. Y

Additional objects, advantagesand features of invention reside in the arrangement and construction and combination of partsl involvedY in the embodiment of the invention as set forth hereinafter or as will be understood from the following description and accompanying drawings, wherein n Figure 1 is' a fragmentary longitudinal section taken in a plane indicated by the line I-I Figure 3, and showing the reciprocable bolt in full lines in forwar'dmost position andl in dottedl lines in retracted position with the gun adjusted for retarded re.

jigure 2A is a detail sectional View on line 'if- 2 of Figure showing the trigger and primary scar in released' positions.

Figure 3 is a plan view of the trigger frame and action parts carried thereby;

Figure 4 isa cross section on the line ll-f-vof Figure 1, looking toward the butt of the weapon;

Figure 5 is a section on the line 5^5 of Figure 1;

Figure 6 is a horizontal sectionv on' the lineV4 6--6 of Figure 1;

Figure '7 is a bottom plan view of the manual adjustment for shifting between full automatic nre and retarded .automatic fire'.

Figure 8 is a cross section on the line 8'! of Figure 3.

Figure 9 is a section correspondingA generally to Figure 1,` but showing the retarder or cam bar adjusted to its forwardinost position t'o cut out retarded fire and effect full rate of automatic lire, and,

Figure 10 isa section` corresponding to Figures 1 and 9, but showing the position of the parts at let-off in retarded re.

Referring to the drawings, there is illustrated al portiony of a. receiver I 0 conventionally indicated, in the lower part of which a. trigger frame l II is secured. This frame is open at itsfrear end and otherwise may be' shapedA and secured in the same position heretofore occupied by other forms of trigger fram-es in the same general form of gun action;

This gun in a priorformto which my invention is applicable, is illustrated in the patenty to Browning, Number 1,393,002 and the patent to Simpson, Number 2,379,461, and others'.

The gun includesv a horizontally reciprocable action slide or bolt i2', of conventional structure and mounting which movesA from: a rear cocked position, as shown in Figure 1, to' a battery' positi'n. forward. Except iol thei seal' retaidin'g second rate control, as desired, and.otlier known safety" arid; auxiliary features are includable as discretion` may'dictate, with appropriate added features to enable such inclusions".

`vertical plane of the frame.

2,509,530 Y -v e The action slide may be a part of or may carry the bolt of the gun and may be operated by gas from the barrel as in the above mentioned patents, or may be otherwise operated in accordance with practices known in machine guns.

The slide I2 includes a cross head i'I at its extreme rear part, movable closely over the trigger frame, including the upstanding bumper plate I8 and a horizontal bar or plate I3 at its lower side. In the lower face of the latter the usual sear notch is formed, having the usual shoulder 2| at the rear side to engage the sear as heretofore.

The trigger frame II comprises side walls 22 and a lower connecting forward bottom 23, intermediate trigger guard 24, and rearward pistol grip the latter being hollow and extended downward from the rear end of the receiver. The said side wallsl 22 are of low altitude and have rectilinear upper edges intended to abut snugly corresponding surfaces of the receiver when pressed upwardly into assembled position. At its forward end, the frame II has aV transverse wall 25 on which a forwardly projected horizontal rib 2'I is formed, adapted to engage a slot or socket in the'receiver for support or for other purposes.

The bottom 23 is longitudinally channelled on the upper left side as at 28, to receive a reciprocable retarder bar or cam member 3!! having at its forward end a guide rod 29 which, at

its normal forward position, stops at the wall 26. The wall 25 is apertured for entry of the rod at times, however, as will appear. The rod is engaged slidably through a transverse guide and seat wall 3| spaced a distance rearward of the wall 25. The bar 30, in its major intermediate part, is rectangular in cross section and at the base of the rod 25 is formed with a raised angular lug or strike 32. This lug is positioned to be engaged by bolt I2 as the latter moves forwardly to battery position to thereby correspondingly move the bar. Confined between the bar and seat wall 3l there is a helical spring 33 engaged loosely around the rod 29 and constantly urging bar 3B rearwardly. Y Over the trigger guard, and rearward thereof, the body of the frame is deepened for its full width, to afford a trigger and escapement chamber 34, open at the rear end of the frame. From the rear part of the chamber a well 35 extends downward to the hollow in the grip 25. A narrow longitudinal channel 36 is formed in the bottom of the chamber 34 from the well forward and also an opening 35 through the bottom of the channel 36 to the space within the guard 24, this opening being in the medial But the channel 36 is broader than the opening 36 and extends to the right wall 22 of the chamber 34.

In the opening 36 a finger piece 3'! of a trigger 38 extends downwardly, the upper part or shank 39 thereof being pivoted on a pin 39' inserted through the walls of the channel 35. See Figure 2. The trigger 38 consists of a lever formed integrally on the shank 39, but offset to the right of the medial plane of the action (to the left as viewed in Figure 4), so as to be out of line with the bar 30. This offset lever includes a forward arm 40 cupped on the lower side to retain the upper end of a compression spring 4I set on the oor of the channel 36; and a, simple rear arm 42 of short length.

A primary sear 43 is pivoted on a pin 43' between the side walls 22, a, distance rearwardly of and `above the trigger, having a rearward sear leg or heel 44 of a conventional form and relation to 4 the action slide, and shaped to enter the notch 25 to engage the shoulder 2l as usual, under urging of a compression spring 45 set in a recess in the under side of the arm 44 and another recess in the floor of the chamber 34.

The forward leg 46 of the sear (see Figure 2) is formed with a depending lug wiper or presser 47, over the end portion of the trigger arm 42. A recess 48 is formed in the under side of the leg `45, having a flat top face 49 which is approximately horizontal, and a step 5i! is formed at the rear side of this recess including a surface in a plane parallel to and -below the face 49. A stop shoulder 5I is also formed on the leg, below and at the rear of the step 50, a suitable distance from the recess 48 for the functions to be described.

Under the leg 46 of the sear and below the arm 42 of the trigger, an L-shaped dog 52 is pivoted on a pin rearward of the arm 42, the doghaving a forward wiper 53 engaging the under side of the trigger arm and urged upward thereagainst by a light compression spring 54 much weaker than the trigger spring 4I. YAn upstanding rest arm 55 extends radially upwardly from the pivot of the dog, having such length that, with the triggerffree, the trigger arm 42 bears on the wiper 53 and the sear presser 41 bears on the arm 42, while the rest 55 engages against the surface 49 and supports the leg 46, so as to limit elevation of the heel of the sear at raised or cocked position.

The rest 55 has a forward side which will tend to rest against the end of the trigger arm 42 in the extreme forward position of the rest 55. The length of the latter is such as to allow a certain play of the rest 55 in the recess 48, so that the end of the arm 42 at free position, Figure 2, is short of the rest when the rest is stopped in the recess 4B at the step 50, the trigger being stopped in the free position shown by engagement of the lower part of the shank 39 against thefront edge of the opening 36.

The trigger will thus be checked by the rear wall of opening 35 in its depression or firing movement at a position in which the forward portion of the sear 43 will not be elevated to a position with the stop 5I above the rest 55 of the dog 52.

With the construction of the trigger and sear action described, the gun may be operated for conventional rapid iire without other operative parts, and it is an advantage of the invention that this function may be carried out without impairment if the rate retarding elements hereinafter described become impaired or blocked.

In the use of the trigger andprimary sear, the bolt or slide I2 being retracted, the sear enga-ges in the notch 25 to cock the weapon, as familiar in prior guns of the general type.V The shoulder ZI engages against the raised end or heel of the sear to hold the slide against forward movement by the driving spring usually employed in such guns. On pulling the nger piece of the trigger, counterclockwise rotation of its rear arm 42 elevates the presser 41 and forward leg 45 of the isear, the spring 54 causing the-wiper 53 to follow and the rest 55 to move rearward to the forward edge ofthe step 50, where it isstopped momentarily while rising motions of the trigger and Sear parts 42 and 4l continue. The arm 42 rises from the wiper 53 during the last mentioned continued movements. As soon as the trigger has reached its firing or let off position sear arm 46 will have Amoved sufficiently for the rest 55 to pass rearward under the step 50, upward pressure of the spring 54 causes clockwise rotation of the dog 52 which sweeps the rest 55 under the step 58. At this let oi position of the dog and sear the shoulder 2|- will have just slipped off the sear heel 44, and the` gun goes into auto-` matic fire. The dog 52 before this time serves as a partial release preventer by reason of its frictional engagement with the rear wall of recess li9 due to pressure of spring 54, this pressure being applied to the sear at a point below its center of rotation, and'after let off operates as a partial engagement preventer, so that wavering of the trigger cannot cause slight movements of the Sear which. might interrupt the motion of the slide l2. In addition, the dog 52 operates as a quick-full-stop sear control, by preventing any engaging or cooking movement at all by the sear until after the trigger has moved sufficiently toward initial free position to permit full movement of the sear into the. notch of the slide. In such release movement of the trigger, the wiper 53V is pressed downwardly, sweeping the rest 55 forwardly along the step 50, the arm 42 of the trigger moving into spaced relation to the presser el for the time being; and on completion of the desired extent of release movement of the trigger, the rest 55 clears the step 58, permitting the sear to move by its spring suddenly and' fully to cocked position, where it engages in the notch 28 on the completion of the next rearward travel of the slide I2.

The barr 3i) has a downwardly inclined rear end portion, in the chamber 34, to the left of the tri-gger body 38, and sear 43, such portion being slotted longitudinally on the under side as at 58, a rack 5l being pivoted therein for vertical swinging; movement in line with a ratchet wheel 58 revolvable on a pin 59 set crosswise inthe opening 34. A larger escapement ratchet wheel '6U is xedconcentrically with the wheel 58. Below the escapement wheel, in the hollow grip 25, there is pivoted a pendulum weight 6l, having pallets S2 set in operative relation to the teeth of the large ratchet, so that rotation of the latter will oscillatey the pendulum. Under the rear end of the bar 3l!-` over the rack 51 a spring 63 is conned to hold the rack yieldingly engaged with the ratchet wheel 58. The forward end of the rack. lever 51 is extended to provide a heel to engage the under side of the bar 3D and prevent the rack rom being depressed too far, especially during assembly.

rlhe right side of the: bar 30 over the-chamber 34 is relieved to afford more space for other parts, and at the left side of the space in the trigger trame a secondary sea-r 65 is pivoted on the scar pin 43', the searhaving a sear heel end 66 to engagein the notch 20. It is` formed with a rearward tongue Sl at the lower part extended beyond the well 35 and cupped to receive the upper end of a coil spring '58V the lower end of which is set in a recess in the bottom of the chamber 34 beyond the well. The sears 43' and 65 occupy the full width of the spacev between thev side plates 22 of the trigger frame, and are independently pivotable on pin 43. The forward leg 69 of the secondary sear is narrowed forwardly of thev pin c3 to forma normally vertical shoulder 'l5 (Figs. l, 9 and 10), and is extended a distancebeside the relieved rearA end of the bar 3D. The top of the latter is formed with an upwardly facingL inclined plane cam face l0 extending from the top or the bar downwardly toward the rear tov a level below and rearwardly of the extremity of, the leg; 5,9.

The extremity of the: legv 8,9` is provided with a pin 1I at its left side over the cam 10, on which a roller 'l2 is journaled to travel on the cam during retarded lire operation. It may be noted that the sear spring 68 serves to hold this wiper in proper bearing on the cam. Puearward of the cam 1Q, there is an abrupt upwardly and rearwardly inclined cam face 13, formed on the top of the bar 30, terminating at an elevated at 14. This construction is such that, when bar 30 is moved to its forwardmost position, flat. 'M is moved beneath roller 'I2 and acts to pivot secondary sear 65 clockwise to a position clear of bolt |28. AV cup is formed on the under side of flat 'i4 to accommodate the spring 63. The parts are so constructed, proportioned and related that rearward movement of bar 30 is limited by abutment of its rear end against shoulder 15, as seen in Figure 1G. When the parts are in the position shown upon this iigure, the secondary sear 61 has been pivoted clockwise, free of bolt l2, by rollerl T2 as it rides up on cam surface 10.

In order to placev the gun in unretarded automatic hre, with the normal functioning of whatever ring mechanism there may be used, and controlled only7 by the primary sear, a locking device 15 is adjustable on the under side of the channelled bottom 23. This involves the formation of a short channel TI in the under side of the bar 38 and theI location of a rectangular nut l8- slidably therein, into which is screwed from below the shank of a headed pin 7-9 engaged through a longitudinal slot 80, formed through the bottom 0I" the channel 218 of the trigger frame. The slot is wide enough to permit the pin to be moved longitudinally therein. The slot has circular enlargements 8|v at each end smaller than the nut-18 and the' pin is engaged through a knob 82 having al circular base adapted to t snugly in either hole 8l.

The knob is cou-nterbored to receive the head of pinlg. A protractileV spring 83 is confined between the head ofthe pin within the counterbore and acts to press the knob inward toward the nut 'I8 as is obvious from Figure 8i. In use, by pulling outward on the knob 82', the spring 8-3' isv compressed and the knob 82 is withdrawn from the hole at eitherv endof the slot. 86, permitting sliding movement of the nut 'I8 and pin to the other end of the channel. and slot', whereuponV release of the knob permits spring 83.v to press knob 82` into the newly aligned' hole 8i. The. rear hole 8'! is so located that when the knob isV therein; the rear; end of the bar S8 when free of slide l2 will engage the shoulder l5 of sear 65 under the rearward urge of spring 33, thus determining the rear limit of travel of the bar 30. The forward hole; 8 li, is solocated that when the knob is moved thereto the` nut engages the forward end of the channel Tl and moves the bar 38 tothe position shown in. Figure 9 wherein flatV T4: engagesv beneath roller 12 and pivots secondary'sear 85 clear' ofi bolt l2. The gun is then adjusted and operable for its normal high rate of lre.

If the button is adjustedto its. rear position, thebar 3,0' is moved by its spring 33:I (which tends to hold it at the; rearmost limit; of. movement) against the shoulderI 1x5. The: bar is then movable forwardlyy with slide l2. by engagement of the.: bottom bar lothe slide against' the lug 3:2. The slide 3i): is shown in Figures 1 and 3 in'its forwardl limit ofmotionunder theI action ofI slide l2. It is stopped atthisposition by the nut T8, provided the knob B2- isl in. the rear hole 8|'.

'lhezdelayeda automatic action. atV all times subject to the trigger and primary scar, full depression of the trigger permitting the retarded re operation of the mechanism and full release of the trigger stopping lire.

When the trigger is pulled while the device is set for retarded automatic re, the cross bar I9 of the action slide moves forward a distance during which the new cartridge is being started in the gun chamber; and before the bolt reaches battery position the bar i9 engages the lug 32 and carries the retarder bar 30 forward, the bar continuing in this movement and compressing v the spring 33 until the bar 30 is stopped by engagement of the rear end of channel 11 with the nut la.

In this forward position of the retarding bar Bythe cam 'it will have permitted the roller 12 to drop to its low position on the cam, as shown in Figure 1, by operation of the spring 68 in raising the scar 65 to cocked position.

In the forward movement of the bar 30 the rack l is drawn with it, rising against force of the spring 655 sufficiently to slide over the teeth of the ratchet 58. As the bar is started rearward by the spring 33, the rack engages and tends to turn the ratchet clockwise, as viewed in Figure 1. But such rotation is delayed by the pallets 62 engaging the wheel G, and inertia of the pendulum el, so that the sear 65 engages in the notch 2) of the buffer and counter recoiling slide, holding the latter in cocked position until the delayed release or let-oli' of the sear 65 is eiiected by the rearward return of the retarder bar 33, and consequent raising of the roller l2 by the cam surface 1D.

The sear 65 moves out of engagement with shoulder 2i of the notch 20, to fire another round, and the bar 3% is stopped in its rearward movement before the roller 'I2 rises above the lower face of the bar I9.

AS the slide l2 moves rearwardly over the Sear, the latter may be depressed by the rear part of the cross head il, and the shoulder 2i may move rearwardly of the sear as the bumper I8 engages the conventional buier head I5, after which the buier reacts and with the usual driving spring of the guns of the kind mentioned, returns the slide to engage the shoulder 2! of the latter with the sear.

It will be seen that by properly proportioning the length and weight of the pendulum to the force of the spring 33, a very denite determination of the time of delay may be attained.

In order to produce the escapement function in this instance the teeth of the ratchet are of simple V-shape, and moderate altitude the angle of each being bisected by a radius of the axisy of the wheel. The pallets are so formed that the pendulum may be reversed side for side without impairing their action.

The pendulum (shown approximately threequarters actual size in the drawing) consists in the present instance of a simple blank of approximately quarter-inch steel sheet stock having parallel side edges and a rectilinear bottom at right angles thereto.

The top is recessed to form at inner pallet races 85 at each side of the recess and the lateral extensions of the body thus formed have their top end faces 86, finished in planes at a small angle to the path of the teeth of the wheel 60, the apices of the pallets spaced slightly more than the same distance as the apices of two alternate teeth of the wheel 60.

The pendulum blank is bored to receive aV pivot pin 88 very close to a line between the apices of the palletsso that these may have substantial componentsl of both vertical and horizontal move'- ment under swinging of the pendulum. The faces 86 at the side of approach of the teeth of the ratchet is at suchan acute angle to the path of the teeth that an engaging tooth point will wipe and cam thereon so as to develop a principal component of vertical force and so will depress this pallet, causing the pendulum to swing to the left as viewed in Figure 1. This raises the left hand pallet so that its apex is in the path of and is engaged by an advancing tooth of the ratchet shortly after.l The last named engagement, by inclination and downward pressure of the advancing face of the ratchet wheel tooth and the horizontal component of angular movement of the pallet on its axis result in depression of the left pallet and swinging of the pendulum to the right, bringing the parts to the rst mentioned relation.

The relatively low height of the ratchet teeth and the described relation of the pallet faces is conducive to easy rapid oscillation of the pendulum and a minimum of wear in the teeth and pallets. The weight of the pendulum has been made approximately one half ounce, utilizing a spring 33 with an expansive force of approximately onerpound at maximum compression by the bar 30. Y I

We have disclosed our invention with particularity` in thegbest form in which it has been constructed, and perfected by us, but it will be understood that this is purely exemplary and that various changes in structure and arrangement, substitutions of materials and equivalents, mechanical or otherwise, may be made without departing from the spirit of the invention particularly set forth in the appended claims, wherein we claim:

l. A retarding device for use in automatic fire of a machine gun having a notched action slide with a crossmember thereon and a sear to engage the slide notch; comprising a frame having a trigger, a channel formed in the left side of said frame parallel to the slide path, a

nally downward toward the rear under said wiper,

an operating spring for said bar to urge it rearwardly, said b ar having a raised lug at its forward endinthe path of the cross member and spaced from said cam a distance sulicient to be engaged bythe cross member in counter recoil and moved a distance equal to the length of the `normal working face of the cam, the cam face under the wiper at the last named position of the bar having an altitudeto position the retarding sear in full cooking position, means to stop the bar at a firing position, the cam face under the wiper at the last named position having an altitude to position Ythe retarding sear at let off position, a rearwardly rising cam rearwardly of the VIirst cam on the bar and having a maximum rear altitude sufcient to move and support the wiper at let off position, and manually operable means to move said bar to, and secure it at, an exceptional forward position with the second cam operative as stated.

2. The structure of claim 1 in which said means to retard movement of said bar comprises a rack pivoted on the lower side of said bar and having teeth on its underside, a rack-engaging gear revolvable on a transverse axis in the frame rearwardly of the trigger, said bar extending over the rack, a spring confined between the rack and the extremity of the bar, an escapement wheel xed with said gear, and a pendulum pivoted below the said wheel and having pallets operatively engaged with the wheel.

3. A retarding device for use in automatic re of a machine gun having a slide, and a sear and trigger mechanism operatively associated with the slide, said retarding device comprising a retarding sear adapted to be moved into and out of engagement with the gun slide, a cam engaging the retarding scar and in one position permitting movement of the retarding sear into engagement with the gun slide and in another position moving the retarding sear out of engagement with the gun slide, the slide being reciprocable to move said cam to said one position during automatic firing of the gun, and manual means to move the cam into a third stationary position where the cam engages the retarding sear and holds it out of engagement with the gun slide.

4. The structure of claim 3, a spring urging said cam towards said other position and an abutment connected to said cam and normally arranged in the path of the gun slide to be engaged by the gun slide to move the cam to said one position.

5. In the structure of claim 3, means to retard movement of the cam to its said other position.

6. The structure of claim 3, in which said cam reciprocating means comprises a spring urging the cam toward said other position and an abutment connected to said cam and normally arranged in the path of thesgun slide to be engaged by the gun slide to move the cam to its said one position, and means to retard movement of the cam to its said other position.

7. In a rate of re retarding mechanism for an automatic rapid re gun having a slide reciprocable between shell loading and extracting positions, a sear movable into a position engaging and retaining said slide in extracting position, first spring means urging said sear into slide-engaging position, a movable cam member operable in a first position to move said sear free of said slide and in a second position to free said sear for movement into slide-engaging position, second spring means urging said member to first position, and escapement means connected with said cam member to retard movement thereof into said rst position.

8. In a rate of fire retarding mechanism for an automatic rapid rire gun having a slide movable between forward and retracted positions, a sear movable into a position engaging and retaining the slide in retracted position, first means urging said sear into slide engaging and retaining position, a movable cam member operable in a first position to move said sear free of the slide and in a second position to release said sear for movement into slide-retaining position, second spring means urging said cam member into. rst position, escapement means retarding movement of said cam member into rst position, and means carried by the slide for engaging and moving said cam member into second position in response to movement of the slide to forward position.

9. In a rate of re retarding mechanism as recited in claim 8, said cam member being constructed and arranged to engage and move said sear free of the slide when said member is moved to a third position, and means connected with said cam member to move and positively hold the same in said third position.

10. A rate of fire retarding device for ruse in automatic nre of a machine gun having a slide, a iirst sear operable to engage and release the slide and a trigger operatively associated with the sear, said retarding device comprising a second sear independently cooperative with the slide of the gun, spring means urging said second sear into slide engaging position, a reciprocating cam member movable parallel with the slide path, a spring urging said member to rear position, said second 4sear being movable by said member into position free of slide when said member is moved by said spring to rear position, said cam member releasing said second sear when in forward position, the slide engaging and moving said member into a :T rst forward position by its own forward movement, said member being manually movable into a second forward position, said member operating to move and hold said second sear free of the slide when in second forward position, and means for moving and releasably holding said membei in said second forward position.

11. In a delayed action ring mechanism for an automatic gun having a barrel and a reciprocable slide operable to successively extract shells from and load cartridges into said barrel, a sear pivotable from a first position free of the slide to a second position to engage and hold the slide in rearward position, first spring means urging said sear into second position, bar means having a cam surface operable when moved from a second to a rst position to engage and move said sear from its second into its first position, against the action of said rst spring means, said bar means being engaged and moved into its second position by forward reciprocation o1 the slide, second spring means urging said bar means into its said first position, and delay action means resisting movement of said bar means into its first position.

l2. In a firing mechanism, a reciprocating liring member, a Sear pivoted thereadjacent having a heel movable and spring-urged into the path of the firing member and having a forwardly extended operating arm, a cam having a cam face under said arm, means responsive to operation of the firing member to move the cam and sear divergently, and then convergently with the cam oblique to the path of their relative movement for let-01T, and means to retard said convergent movement.

ORVAR E. ROSENGREN. OSWALD O. SUNDERLAND.

REFERENCE S CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 1,318,214 Logan Oct. 7, 1919 1,573,655 Sutter Feb. 16, 1926 2,088,877 Stange Aug. 3, 1937 2,116,140 Browning May 3, 1938 2,363,966 Ironside Nov. 28, 1944 FOREIGN PATENTS Number Country Date 706,665 France Mar. 31, 1931

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