US2654175A - Trigger mechanism - Google Patents

Description

Oct. 6, 1953 M. HANSEN TRIGGER MECHANISM Filed Oct. 1, 1949 INVENTOR. MAUR ICE HANSEN ATTORNEYS,

Patented Oct. 6, 1953 TRIGGER MECHANISM Maurice Hansen, San Mateo, Calif., assignor to Samuel I. Keene, San Francisco, Calif.

Application October 1, 1949, Serial No. 119,115

3 Claims.

This invention relates to a trigger mechanism for small firearms, and has for one of its objects the provision of a mechanism that is readily adapted to existing firearms, and which mechanism is of the type in which the cocking piece is released to effect firing by the release of the finger retracted trigger.

Another object of the invention is the provision of an improvement in a trigger mechanism of the type employed in military firearms commonly known as the Garand or M1, semiautomatic rifles, in which the cooking piece comprises a pivotally mounted spring loaded hammer that is engaged and held in cocked position by a sear and Which hammer is released from such engagement by actuation of a finger retractable trigger. This improvement is one whereby the hammer will be released by a release of the finger retracted trigger from a partial retracted portion of the trigger, but upon a further retraction of the trigger the latter may be released without releasing the hammer.

A still further object of the invention is the provision of a means in a trigger mechanism whereby the point at which the cocking piece is adapted to be released by the movement of the trigger is very pronounced, so that the user will be apprised of the fact that further movement of the trigger will result in a release of the cocking piece.

Another object of the invention is the provision of a trigger mechanism of the type in which release of the finger retracted trigger from a predetermined point in its retractive movement will result in releasing the cocked cocking piece, and in which mechanism means is provided for clearly and unmistakably indicating to the user when said point is reached during the retraction of the trigger so that the trigger will not he accidentally retracted past said point. Furthermore, means is provided in the trigger mechanism whereby the trigger may be pulled past said point by application of substantially greater force than was required to retract the trigger to said point, and

which this release of the sear from said holding relationship is one that is acquired only after long familiarity with the firearm, Inasmuch as there is no particular uniformity in this respect in different firearms, the user must repeat the procedure of familiarizing himself with each firearm before he knows substantially the moment when a further retraction of the trigger will effect a release of the cooking piece. There are individuals who allege that the user should not know the point, during retraction of the trigger, when the cooking piece will be released, but the experts are in substantial uniformity in admitting that they are aware of the point where the cocking piece will be released and utilize this knowledge to their benefit. Furthermore, it is generally conceded that the greatest accuracy, particularly where .quick accurate shooting is required, may be obtained by use of the so called hair trigger, so the user will be able to fire the piece at the exact moment when the sights are aligned on the objective, and before they waver out of alignment.

However, the use of the hair trigger is not permitted by the rules governing regulation tournaments because of the danger from accidental discharge of the firearms. The rules usually require at least a three to four pound pull on the trigger before the same will release the cooking piece.

With the present invention, the required pull is provided,'yet the user may completely ignore the slow trigger squeeze procedure and immediately bring the trigger to the point where a slight release of the trigger at that point, such as would occur by merely moving the end of the trigger finger forwardly an imperceptible amount, will result in releasing the cocked cocking piece. This release of the trigger, instead of further retraction, for efiecting the firing of the piece, is important in the present example for the 1 reason that the user need have no fear of releasing the cocking piece through pulling the trigger.

Should he go past the point where a-release of the trigger will release the cooking piece, the latter will not be released. Such a movement will merely nullify a release of the cocking piece when the trigger moves forwardly, and the user can again retract the trigger to the desired point and release the cocking piece in a fraction of the time it would take to go through the traditional trigger squeeze procedure.

Other objects and advantages will be apparent from the description and claims.

In the drawings, Fig. 1 is a fragmentary perspective view of the trigger mechanism of an M1 rifle removed from the latter, and with the present invention therein. The hammer is shown in this figure in cocked position and with the trig- ,ger forward.

Fig. 2 is a fragmentary side elevational view,

showing the relationship between the several elements of the present invention to the hammer, in which the hammer is cocked and the trigger in normal forward position. Certain parts are broken away to show internal structure, and the conventional frame is omitted.

Fig. 3 is a view similar to that of Fig. 2 except that the parts are indicated in the position they assume when the trigger is retracted to the point where a release thereof will result in releasing the cocking piece.

Fig. 4 is a view similar to that of Figs. 2, 3, but with the trigger substantially fully retracted so as to permit release of the trigger without effect ing a release of the cocking piece.

Fig. 5 is a view similar to that of "Figs. 2, 8, 4, but in which the hammer is out of engagement with the sear, being in uncooked position, and is therefore omitted, and in which part of the main spring for yieldably holding the trigger in forward position is indicated, together with part oi the barrel enclosing the .sa-md, 31111331813391 being indicated partly insection.

Fig. 6 is an enlarged, fragmentary sectional view showing the means :for indicating the point at which a release of the trigger will release the cocked cocking piece.

Fig. 7 is a fragmentary view of a different form of the invention for compression In detail, the hammer or cooking piece is indicated at The term hammer used herein may apply to any wring aurged cocking piece that effects the firing of the firearm when released. in the present instance, the hammer that illustrated corresponds with that used in the semiautomatic military :rifle, commonly known in the military service as the M1 or 'Garand? In fact, most or the mechanism illustrated, with the exception of the elements directly connected with the trigger, are standard on the :above noted military ride.

The hammer i swings about a pivot 1 that is carried :by frame 3 and said hammer :is retracted against the tension of an expansion coil spring 4 that in turn is substantially enclosed minder compression) within a barrel 5.

In ,Fig. 1, the hammer is retracted to cocked position and is adapted to swing forwardly, or clockwise, about pivot 2 when released. The term forward or fiorwardiy in describing the elements or movements refers to locations having reference to the stock being at the rear end and the muzzle at the forward end. Thus the hammer when released will swing forwardly" or toward the muzzle end of the firearm, and when retracted, it will be moved rearwardly;

The rear .end of barrel 5 is adapted to have some generally vertical movement relative to .a pivot pin .6, which pin constitutes the pivot about which the trigger, generally designated '1, is adapted to swing. Opening 8, indicated in Figs. 2 to 5 is for pivot pin 5. The rear end of spring 4 reacts against the rear closed end of the barrel 5, while a cross bar 9 at the forward end of the spring is supported between opposed cars 10 (only the near ear being seen in Fig. l, and within a, corresponding arcuate crossgroove 'll formed in the rear side of the hammer between pivot 2 and the upper end of said hammer. Ears I 0 are connected by plate lit at their rear ends, and a rod (not shown) extends centrally from said plate into the center of spring 4. The forward end of said spring reacts against plate [2, whereby the spring will tend at all times to drive the hammer forwardly. and the spring will be un er projections I9 (only the near one being shown in Fig. 1), on the base I! of frame 3, which lbase provides the upper side of the finger opening into which the lower end of the trigger protects domrwamlly. The conventional trigger bowor guard defines the rest of said finger opening. Frame 3 includes .all stationary parts for supporting the trigger mechanism.

The ears 5 at the rear end of barrel 5 'form the opposite sides of a rearwardly opening clevis projecting .rearWa'rdl-y from rear end wall 23 of barrel 5. The rearwardly facing surface of wall 23 between ears I5 is formed with a horizontally extending 'rearwardly opening groove or notch 25 into which forward sharpened ends of members 26,tha-t are integral with the trigger, are adapted to fulcrum. Inasmuch as said projections are located slightly above the axis of pivot 6, it will be seen that the force of the spring in barrel 5 will tend at all times to swing the lower end 21 of the trigger forwardly and to yieldably resist retraction of the trigger by the trigger finger.

The lower end 2 of the trigger is the finger engaging portion of said trigger, and the members 26' are formed on the forward edges of a portion 28 that projects above the finger engaging part 27 of said trigger. Thus portion 28 is .split to provide opposed sides. Projections .26 are formed on the forward edges of said sides.

The portion 28 is ofiset slightly forwardly of the lower part 21 of .the trigger, but is integral with the latter. Directly above said part 21 and rearwardly of portion .28 is an upwardly directed surface 29 for a purpose later to be described.

Pivotally supported between the forward marginal portions of the spaced vertical sides that form portion 28 isa generally vertically extending auxiliary sear .30 that is pivoted on pivot 6, at a point intermediate the upper and lower ends of said sear.

The lower end 31 of said auxiliary sear is at about the .same level as the upper side 29 adjacent the junction between portions 21, 28 of the trigger. This lower end is directed slightly forward. as best seen in Fig. 5 and between said lower end and pivot 6 (or openings 8) is a spring 32 that reacts between the rear side of the sear and the rear side of portion 28 that connects the lateral sides of the latter between which the auxiliary sear is positioned.

This spring 32 at all t'mes tends to move the lower end 3| of the auxiliary sear forwardly,

which means that the upper end is yieldably urged rearwardly by the same spring.

At the upper end of said auxiliary sear are oppositely outwardly laterally projecting arms 34 extending transversely past the forward edge of said sear. These are integral with the auxiliary sear, hence move rearwardly when the lower end of the auxiliary sear is moved forwardly, and vice versa.

Th? hammer I .is formed with rearwardlv and downwardly projecting arms 35. When the hammer is cocked, or swung rearwardly, the lower ends of said arms move to opposite sides of the upper end of the auxiliary sear, and rearwardly of the arms 34 on the latter. At the lower ends of each of the arms 35 are forwardly and rear- Wardly extending projections 33, 31 (Figs. 2, 3). When the hammer is cocked, the forward projections will engage the inclined upper cam surfaces of arms 34 causing the latter to swing forwardly (compressing spring 32) and as soon as the projections pass below said arms 34, the latter will snap over projections 33 under the influence of sprin 32 to hold the hammer cocked.

Directly above the lower part 21 of the trigger and below the surface 29, the trigger is recessed to provide for receiving a horizontally elongated catch element 40 that extends longitudinally of the rifle, and the rear end of which is secured to the trigger by a horizontal pivot 4|. Below said catch element is a small spring 42 that engages the underside of element 43 forwardly of the pivot 4| for yieldably urging the forward end of said element upwardly. Said forward end is formed with an upstanding projection 43 that is adapted to be engaged by the lower end 3| of the auxiliary sear so that when the lower part 21 of the trigger is retracted this movement will cause the lower end of the auxiliary sear to also move rearwardly whereby the arms 34 at the upper end of said auxiliary sear will move forwardly from above the projections 36 on the lower ends of arms 35 of the hammer. However, before said arms 34 release the projections 36, the main sear 44 on the upper end of trigger I will pass over the rearward projections 31 on arms 35 of the hammer, so that the hammer will not be released until the said sear 44 moves rearwardly.

Returning to the upper surface 23 on trigger I just above the lower part 21 of said trigger, said surface will move upwardly when the part 21 of the trigger is retracted by the finger. Secured to frame 3 of the trigger mechanism (which is stationary with the firearm) and rearwardly of the trigger, is a block 45 having a forwardly extending projection 46 (Figs. 2, 3, 4 and 6) that extends over said surface 23 and that is spaced above the latter. This portion is formed with a vertically directed aperture through which a post I i 41 slidably extends, which post has a head 48 (Fig. 6) at its lower end.

A relatively light outer spring 49 reacts between said head and said projection for urging the post downwardly, and the upper end of said post above projection 45 has a nut 50 threaded thereon that forms a stop limiting downward movement of the post, a lock nut I above nut 50 locks the latter against accidental loosening.

Within. spring 43 and coaxial therewith and with post 41 is a relatively strong' spring 52 that is slightly shorter than the space between head 48 and projection 46.

Post 41 is so adjusted that the surface 29 will engage head 48 at the moment'the sear 44 on the upper end of the trigger moves into a position holding the hammer cocked and a resistance according to the tension of spring 49 and a slight further retraction of the trigger will cause the spring 52 to set up a quite strong resistance to further retraction of the trigger by the trigger finger. It will be observed, however, that the trigger may be further retracted by exerting a substantially stronger pull sufficient to overcome the tension of both springs 43, 52. t

I Also carried by the projection 43 is a pin 53 that is adapted to extend through an opening in surface 29 and into engagement with the upper side of catch element 40 at a point forwardly of pivot 4| at the moment when the trig-- ger is retracted sufficiently to encounter the resistance of spring 52. Upon further retraction of the trigger against the combined resistance of springs 49, 52, the pin 53 will cause the forward end of the catch element to swing downwardly, thereby releasing the auxiliary sear 33 so that the arms 34 on the upper end will reengage the forward projections 36 on arm and the trigger may then be fully released without causing a release of the hammer.

In Fig. 3 the trigger is shown retracted to the point where the auxiliary sear arms 34 are disengaged from the hammer and where the main sear 44 is holding the hammer cocked. The hook 43 on the forward end of catch element 43 is in engagement with the lower end 3| of auxiliary sear 30. If the trigger, when in this position, is further retracted to the position shown in Fig. 4, the release pin 53 will immediately cause the catch to swing downwardly, releasing the auxiliary sear so that arms 34 will reengage the forward projections 36 of the arms 35 and the trigger may then be fully released without causing a release of the hammer. The projection or hook 43 on the end of the catch 40 will move forwardly with the trigger to a position for again engaging the lower end 3| of the auxiliary sear for moving the latter out of engagement with the hammer when the trigger is again retracted.

In operation, upon bringing the firearm into position for aiming, the user will retract the trigger until it meets with the resistance of spring 52. This resistance is sufficient to stop further retraction of the trigger under normal conditions, even where the person using the firearm may be excited to the degree that is usual in actual combat. Hence, the trigger may be retracted to said point while the firearm is being moved to a firing position.

As soon as the firearm is in a position for aiming, the user need merely retain the trigger retracted to the above mentioned position, while careful aim is taken, and as soon as the sights are in proper alignment'with the objective, a slight forward movement of the outer end of the trigger finger will result in immediate release of the hammer. Thus forward movement of the outer end of the trigger finger suificient to effect release of the hammer is usually so slight as to be almost imperceptible, hence the release of the hammer and consequent firing of the firearm will occur practically simultaneously with the alignment of the sight on the objective where the reaction of the shooter is substantially normal. In actual practice, persons having an abnormally slow physical reaction to a mental stimulus, obtain far greater accuracy in both rapid and slow fire by using the present invention than where the traditional trigger squeeze method is employed.

It is obvious that the degree of forward movement of the trigger required to release the hammer is determined by the degree of engagement -.From the foregoing explanation, it will-be "seen that, by the present invention, virtually a hair trigger :is provided, but which trigger is at least as safe as the conventional trigger, and in most instances .it is safer for the .reason that usually the accidental firing of a cocked firearm-is the result of a force that vis sumcient to fully retract the trigger with the present invention, or else it is insufficient to retract the trigger to the point where further retraction is resisted by the: spring 52. If the trigger is fully retracted the hammer will not be released upon release of the trigger, and unless the trigger is retracted to what may be termed the tell-tale, where the surface 29 engages head 48 of the post H, the hammer will not be-released.

With the conventional trigger mechanism, ac cidental firing of the firearm is almost inevitable where the trigger becomes caught on some object with suificient force to cause a retraction of the trigger.

The double springs 49, 52, provide a means for preventing the hammer from being released un der the influenceof the natural rebound that would sometimes occur where the user retracts the trigger rapidly to the point where spring 52 stops the same. The interval between that the resistance of spring 49 occurs, and that at which spring 52 and spring 49 resist further retraction, is very slight, and is sufiicient to nullify the likelihood of a rebound of the trigger finger, such as could occur where the trigger to be initially retracted to where spring 52 would resist further retraction without the interposition of the resistance from spring 49. Such rebound could cause an unintentional discharge of firearm, were it to occur.

One of the advantages of the present invention, in addition to those already described, is

the fact that the chances of the user prematurely disclosing his position through firing his firearm, is substantially eliminated. In the case where the firing of the firearm is through retraction of the trigger, the excited shooter many timesretracts the trigger before he realizes it, and before taking careful aim. The result is that his position is immediately betrayed to the enemy or to game, and the advantage of a surprise is lost.

The making of spring 52 sufficiently stifi or strong to resist all but an intentional pull for rendering the trigger safe to release, does not in any way interfere with the accuracy of aim' nor does it tend in any way to reduce the accuracy with which the firearm may be fired. Once the finger has retracted the trigger to where its further retraction is resisted by spring 52, the trigger finger will be under static tension, and it can be held under such tension almost indefinitely without causing wavering of the firearm through anxiety or nervousness. This cannot be done where the finger is under dynamic tension, or is moved against the load of the main spring, as in the case of conventional trigger, mechanisms.

It might also be added that the present arrangement in semi-automatic model M1 service rifie results in a much faster release of the hammer. In the conventional system, the rear projections on the hammer frictionally engage a member that is on the trigger during the travel of the hammer after its release. The scar in said system engages the forward projections 36 and are released therefrom.

The shorter the period of time between the time when the hammer or bolt is released, and

the firing ,pin causes discharge of the cartridge, the greater the accuracy that. may be obtained in firing any firearm. Considerable eiforts have been made to shorten this time, such as short ening the length of travel of the cocking piece and increasing the strength :of the spring. However in the above rifle, the speed of the hammer .is objectionably slow, except where "the present invention is used.

In Fig. 7 it will be notedthat the elements ployed .are substantially the same as in the other views. However, in this form :of invention a block 15 secured to base 11:1 has a forward projection 16 that is provided with a downwardly projectingifinger fl 1 at its forwarder-id. A catch element 18 similar to catch element -40, except that it is provided "on its upper surface with an upwardly extending projection 19 adjacent its-rear end, said rear end being piv-' plied to the trigger at 8t. Spring 61 'belowl'said element tends to urge the forward end :82 upwardly at all times, and said forward end projects upwardly the same as "the end 43 o'felement 40.

In the present instance,;-th'e main sear, designated 83 substantially the same as sear 4'4 except that its forward upper end 8:1 is not quite as sharp as the forward'edgeof 'sear 44, and does not have quite the same .manner of holding the hammer. However, auxiliary sear 85 is the same as the auxiliary sear -3il,'=and the arm '86 lower end B on said auxiliary sear 85 are the same as arm 34 and end :31 of sear 3-6. Spring 88 tends to urge the lower end it: of scar 85 forwardly at all times.

In operation, upon full retraction of trigger 90 (Fig. 7:) the sear 83 and arm 36 will assume the same position as the sear 44 and arm'M in Fig. 4 and the projections 36, 37 on hammer 35 will be engaged below both sears. However, upon releasing the trigger, the projection 19 is so positioned that the forward end 82 of the latch member will engage the lower end '81 'of the auxiliary sear and will cause the arm 86 to hold the projections 36 of the hammer when the main sear 84 has slipped from holding position on the hammer to a position in which the forward somewhat flattened projection 8'4 is behind the projections 31 "of the hammer.

When in this position, should the person not wish to 'fire the piece, the trigger may be merely released, and the auxiliary sear will hold the hammer cocked.

However, to fire the piece, only a very slight retraction of the trigger from the position above described is necessary. The trigger may be then said to be practically a hair trigger, except that any number of pounds may be required to hold the trigger in the retracted position preparatory to firing.

If the trigger is fully released, the sear 83 will again engage the hammer, requiring another full retraction of the trigger and a release to the tell tale or point where the catch snaps up into engagement with the lower-end of sear '85, and thereafter the slightest retraction of the trigger will effect the release of the hammer.

. It is seenthat both forms of the invention have this in common, namely; a full retraction of the trigger will not cause the hammer to be released, a full release of the trigger after a full retrac tion will not result in releasing the hammer. The hammer will be released only after a movement of the trigger to a predetermined identifiable point, between a full retraction and a full release. In the case of release fire, this latter point is reached by a retraction of the trigger to said point, whereas in the case of compression fire, the point is reached by a release of the trigger from full compression to said point and then a retraction. In both instances the trigger is oscillatable between opposite ends of its stroke, and in both instances the trigger is moved from one end of the stroke to an inter mediate point before a further movement of the trigger will cause the release of the hammer.

I claim:

1. In a trigger mechanism having a cocking piece, a spring, a frame supporting said cocking piece for movement from an uncooked position to a cocked position against the tension of said spring, a finger retractable trigger pivotally supported on said frame for movement from a forward position to a retracted position and vice versa; holding means connected with said trigger for movement relative thereto and into engagement with said cocking piece when the latter is moved to said cocked position, a sear out of engagement with said cocking piece when the latter is in said cocked position and connected with said trigger for movement into such engagement for holding said cocking piece cocked when said trigger is retracted to a predetermined point in its retractive movement less than its full retractive stroke, means connecting said trigger with said with said cocking piece upon movement of said trigger from said point toward said forward position, a spring loaded element, means connected with said trigger for movement therewith into engagement with said element upon said trigger being retracted to said point, said element being movable under the tension of its spring upon further retraction of said trigger past said point, and means actuated by retractive movement of said trigger past said point and against the resistance of said element for restoring said holding means into holding relationship to said cocking piece during said further retraction and upon release of said trigger after such further retraction.

2. In a trigger mechanism having a cocking piece, a spring, a frame supporting said cocking piece for movement from an uncooked position to a cocked position against the tension of said spring, a finger retractable trigger pivotally supported on said frame for movement from a forward position to a retracted position and vise versa; holdin means connected with said trigger for movement relative thereto and into engagement with said cocking piece when the latter is moved to said cocked position, a sear out of engagement with said cocking piece when the latter is in said cocked position and connected with said trigger for movement into such engagement for holding said cocking piece cocked when said trigger is retracted to a predetermined point in its retractive movement less than its full retractive stroke, means connecting said trigger with said holding means for moving said holding means out of holding engagement with said cocking piece upon said trigger being retracted to said point and said sear being movable out of engagement with said cocking piece upon movement of said trigger from said oint toward said forward position, a spring loaded element, means connected with said trigger for movement therewith into engagement with said element upon said trigger being retracted to said point, said element being movable under the tension of its spring upon further retraction of said trigger past said point, and means actuated by retractive movement of said trigger past said point and against the resistance of said element for restoring said holding means into holding relationship to said cocking piece during said further retraction and upon release of said trigger after such further retraction, said spring for said cocking piece being connected with said trigger for constantly urging said trigger to its said forward position.

3. A trigger mechanism comprising a frame having a trigger pivotally supported thereon for oscillatory movement between a fixed forward position and a fixed retracted position and a spring yieldably urging said trigger from said retracted position toward and to said fixed forward position, a cocking piece pivoted on said frame for swinging from a forward firing position to a retracted cocked position, a spring yieldably urging said cocking piece from said retracted position toward and to said cocked position, a first sear on said trigger engageable by said cocking piece upon movement of the latter to its said cocked position for yieldably holding it in said position when said trigger is in its said forward position, a second sear in said trigger movable into releasable engagement with said cocking piece upon retraction of said trigger to a point spaced between its said forward position and its said retracted position for holding said cocking piece in its said cocked position, a movable element on said trigger in releasable engagement with said second sear, and movable with said trigger, a member on said frame positioned to engage said element at a point in the movement of said element with said trigger for moving said element out of holding engagement with said cocking piece whereby said cocking piece will be released for movement to its forward position when it is released from said first sear.

MAURICE HANSEN.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,786,536 Holek Dec. 30, 1930 2,079,039 Razee May 4, 1937 2,136,511 Jones Nov. 15, 1938 2,277,561 Roemer Mar. 24, 1942 2,350,833 Seitz June 6, 1944 2,406,980 Young Sept. 3, 1946 FOREIGN PATENTS Number Country Date 575,000 Great Britain Jan. 30, 1946

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