US3011282A - Firing mechanism for firearms - Google Patents

Description

Dec. 5, 1961 H. H. sEFRn-:D n 3,011,282

FIRING MECHANISM FOR FIREARMS v Filed Jan. 19, 1959 INVENTOR HARRY H. SEFRIED 1I bis Arran/5v5.

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dl LZSZ Patented Dec. 5, i961 3,011,282 FG MECHANISM FOR FEES Harry H. Sefried lll, New Haven, Conn., assignor to The High Standard Manufacturing Corporation, Harnden, Conn., a corporation of Connecticut Filed lan. i9, 1959, Ser. No. 787,489 d Claims. (Cl. t2-69) This invention relates to improvements in tiring mechanisms for firearms, and it relates more particularly to sear means which will provide a crisp trigger and at the same time prevent accidental discharge of the firearm.

ln target shooting, it is extremely important to reduce r to eliminate, if possible, anything which distracts the marksman from keeping his sights on the target at the instant he lires the gun. One of the things which is most distracting to an expert marksman in firing a gun is a noticeable movement of the trigger, known as trigger creep, which he feels as he squeezes the trigger. Such movement is particularly noticeable if the trigger pull is light. A trigger mechanism having a light trigger pull and a very slight amount of movement of the trigger bcfore the let-off point, at which the tiring member is released, is a highly desirable feature in a target gun. 'It is difficult, however, to provide a crisp trigger and a light trigger pull together.

Heretofore only guns which have been extremely accurately made by adhering to close tolerances have had both a light trigger pull and a crisp trigger. 'Such guns, however, must be virtually hand-made and are therefore too expensive for the Vast majority of people who would like to have a target gun with the characteristics required for that type of shooting. Moreover, even in the most carefully manufactured firearm a large degree of safety is usually sacrificed in order to obtain a light trigger pull and the desired crispness in the trigger. This is due to the fact that any shock or jar may cause fall-off of the sear releasing the hammer or other tiring member' that may be employed. Target shooting guns have, therefore, been somewhat more dangerous to handle than other types of firearms.

lt is accordingly an object of the present invention to provide a tiring mechanism with a crisp trigger action, which can be manufactured on a production basis and which will be safe under conditions generally referred to as traumatic. A speciiie object of the invention is to provide a sear which has substantially greater actual sear travel than is normally provided in order to greatly reduce, if not actually do away with, the danger of accidental firing, while at the same time eliminating trigger creep. Another object of the invention is to provide improved sear engagement permitting a light trigger pull as well as a crisp trigger, without detracting from the safety of the gun.

These and other objects of the invention, as well as its novel features and advantages, will become further apparent from the description hereinafter.

in general the invention contemplates provision of interengaging portions of the ring member and sear whereby the initial movement of the Sear out of its cocking engagement with the tiring member requires -a fairly light, but more or less normal, trigger pull; but wherein after a minimum amount of travel of the scar, the angle of the surface, against which the force tending to operate said tiring member is exerted, is changed relative to such force so as to substantially reduce the amount of trigger pull required to release the firing member. -In its most advantageous form, the invention includes the provision of a safety surface on the sear which is disposed at an angle to the latching surface thereof, the latching surface being normally engaged by a cooking-abutment on the hammer or other firing member when the sear is in its full-cooking position, said safety surface being located so that it will be engaged by the cooking-abutment upon movement of the sear from its full-cocking position. The angle which the safety surface makes with respect to the latching surface and the angle which said surface makes with respect to the force exerted on it by said cookingabutment, are such that ir the sear is jarred from its fullcocking position so that the cooking-abutment contacts the Safety surface instead of the latching surface of the scar, the spring means urging the Sear into engagement with the firing member will return the sear to its full-cooking position with the tiring member. On the other hand, when the sear is moved out of cooking position in the usual manner by means of the trigger, the force required to overcome the resistance of the trigger while the cocking-abutment engages the latching surface is so much greater than the force required to move it once the cocking-abutment contacts the safety surface that the safety surface of the Sear will be moved on past the cooking-abutment due to inertia of thevshooters trigger finger alone. In other words, even if the shooter wanted to release the trigger' at the instant the cooking-abutment passes the apex of the angle between the latching surface and the safety surface, he could not do so.

One particularly desirable embodiment of the invention is illustrated in Vthe accompanying drawings, in which FG. l is a side elevational view, partly broken away and partly in cross-section, of a piston incorporating the invention;

FIG. 2 is an enlarged perspective View of the hammer and sear; and

FIG. 3 is a diagrammatic view of the interengaging portions of the hammer and scar within the area defined by the circle in FlG. 2 and shown on a greatly enlarged scale, the hammer and sear being shown lined as if in cross-section.

The tiring mechanism of the semi-automatic pistol of the so-called blow-back type shown in the drawings for illustrative purposes consists of a tiring pin 10 longitudinally movable in a slide l2 which reciprocates longitudinally on the frame i4 in a well known manner. Firing pin lll is urged rearwardly by a spring ll so that its rear end normally projects slightly rearward o-f a vertical wall 16 inside slide i2 in position where it can be struck by a pivoted hammer 1S in order to re a cartridge (not shown) positioned within the chamber of a barrel 20 mounted forwardly of slide l2 and against which slide 12 is forced by a return spring (also not shown).

Hammer lit` is pivoted on a pin 2,2 supported at both K ends in frame i4 and is operated by a hammer spring 24 located in the grip portion of frame 1d on a hammer strut 2d which at its upper end is pressed by means of spring 24 against a pin 2S mounted in hammer 18 in a more or less conventional manner.

vided in the under edge of hammer 18 and through which pin 28 extends. A sear 3.2 is pivoted Vrearwardly of hammer 1S on a pin 3d supported in frame 14. The sear nose 36 of sear 32 extends downwardly and slightly forwardly into a sear notch 38 in the cylindrically shaped rear edge 39 of hammer 18 with the forward tip 40 of scar SZAlatching with the cooking-abutment on the hammer at the lower corner 42 of scar notch 3rd (see FIG. 2). It will be noted that in accordance with usual practice, the direction of the force exerted by hammer spring 24 on hammer 1S when the latter is cocked, is only slightly to one side of pivot pin 22. Consequently, a relatively small force is exerted by sear notch corner 42 on sear 32 thereby reducing the tendency for these members to bind, which would result in an extremely poor trigger action. Moreover, when the hammer falls to the broken line position shown in PEG. l, the full force of hammer The upper end ofV hammer strut 26 lits into a deep slot 30 (FlG. 2) prospring 24 is applied as the hammer strikes the tiring pin 10.

The sear nose 36 of sear 32 is urged forwardly by a sear spring 44 into engagement with the rear edge 39 of hammer 1S so that the front edge of sear nose 36 engages the hammer adjacent the upper corner of sear notch 3S and the tip 4G of sear 32 projects slightly into sear notch '38 into the path of the lower corner 42 thereof. Accordingly, when the hammer is pivoted back (clockwise as shown) somewhat beyond its full-line position as seen in FIG. l during the rearward stroke of slide 12, the nose 4l) of sear 32 will project into sear notch 33 and, on the forward stroke of slide 12, the sear notch corner 42 engages the under edge or sear surface of sear nose itl so that further movement of the hammer is arrested.

A. sear bar 46 extending longitudinally of the frame and actually located outside of the side wall of frame 14, which has been removed in FG. 1 in order to show the firing mechanism, is illustrated in its relative position with respect to the other parts of the gun. Sear bar 46 connects the trigger 48 with the upper end of sear 32 so that when the trigger is pulled, sear 32 will be rotated counterclockwise as shown in FIG. l in order to release hammer 1S and lire the gun. To this end, sear bar 46 is pivoted at its forward end to the upper end of trigger 4S, which in turn is pivoted about the trigger pivot pin Sil. Adjacent its opposite or rear end, sear bar 46 is provided with an upwardly facing notch 52 which receives a lug 54 on the upper end of sear 32. A searbar spring (not shown) exerts an upwardly and rearwardly directed force against the front side of a finger portion 56 on the under side of sear bar d6 in order to resiliently urge notch 52 into engagement with lug 54 on sear 32, while at the same time to urge sear bar 46 longitudinally to the rear. The rearward component of this action will pivot trigger d8 in a clockwise direction as viewed in FIG. l in order to return trigger 48 to its normal position, or to maintain it in that position whenever sear bar 46 is disconnected from sear 32.

Provision for disconnecting the sear from the trigger is of course essential in a semi-automatic firearm of the type here shown in order that the gun will not fire in machine gun fashion if the trigger is held in its retracted position. For this purpose, a hump 53 is provided on the upper edge of sear bar 46 which is depressed by the slide 12 immediately after a cartridge is fired, thereby dropping the notch S2 out of engagement with lug 54 on sear 32 so that the sear can swing back under the urge of sear spring 44 into position for engagement with sear notch 38 as soon as the hammer is returned to cocked position. Sear bar 46 is positively prevented from lifting into engagement with sear lug 54 until slide 12 returns to battery position and the trigger 48 is released so that the sear bar can move longitudinally rearward under the urge of the aforesaid sear-bar spring.

A sear spring adjusting device shown generally at 60 is provided in the rear of frame 14, but since this forms no part of the present invention, it is not described in detail here. In addition, the usual safety notch 61 is provided in case the sear should not engage properly with sear notch 38 or should become accidentally disengaged therefrom.

Referring now more particularly to FIG. 3, the portions of sear 32 and hammer 18 there shown on a greatly enlarged scale are lined as if in cross-section for purposes of clarity. It will be apparent from FIG. 3 that only the sear notch corner 42, sometimes referred to herein as the cooking-abutment of the firing member, engages the under edge of the tip 4G of sear 32 and, therefore, in this instance only a line Contact is made between the cooking-abutment and sear 32. In other words, there is no surface-to-surface contact between the sear notch 38 and the sear nose 36. Consequently, all the force exerted by the hammer 18 bears along this line of contact. The arrow F in FIG. 3, which is perpendicular to a line through the pivot point of the hammer and the corner 42, represents the force exerted by hammer 18 on sear 32.

The primary feature of the present invention comprises the provision of a safety surface 62 on the sear surface of sear 32. Such safety surface in the specific example illustrated in the drawings is formed between the point B, commonly known as the fall-off point, at the front edge of the sear and the point A, which is the apex of an angle formed between the safety surface 62 and the larching surface 64 rearwardly of point A. Point B in the present arrangement is the point at which the hammer is actually released by the seat', and the latching surface 62 is that surface with which the cocking-abutment or sear notch corner engages to lock the hammer 'when the sear is in its full-cocking position. Latching surface 64 is disposed with respect to the direction of the force F exerted by the hammer on the sear at any angle X which may be desirable for the purpose of adequately retaining the sear in engagement with the sear notch corner 42, while at the same time providing the desired trigger pull when the trigger 43 is actuated.

The safety surface 62 is disposed at an angle Y on the order `of 10 to 20 with respect to the plane of latching surface 64. When the sear is moved out of its full-cooking position, in which it is shown in full lines in FIG. 3, to bring safety surface 62 into Contact with the sear notch corner 42, as indicated in dash-dot lines, safety surface 62 forms an angle Z with respect to the direction of cooking-abutment force F. Angle Z may vary considerably depending on several factors, including the magnitudes of the forces exerted by sear spring 44 and the sear bar 46, which urge sear 32 into engagement with hammer 187 as well as the desired angle of engagement of latching surface 64. The general principle, however, which determines the angle at which safety surface 52 should be disposed to the force exerted on it by the cooking corner 42 is, as has been mentioned hereinbefore, that whenever under static conditions the corner 42 engages safety surface 62, the sear 32 will be moved by the forces exerted on it into its full-cooking position, and further that whenever the trigger is manipulated so as to move sear 32 from its full-cooking position to a point where the corner 42 engages safety surface 62, the reduction in the force required to move sear 32, as the corner 42 passes the apex point A, will be so great that there will be no apparent further resistance to the pull of the trigger, rendering it impossible at this point for the shooter to voluntarily prevent the gun from firing.

t will be seen yfrom the foregoing that provision of the safety surface 62 has the elfect of providing a sear travel which is many times that ordinarily used in sear devices of this type, while making only a very small amount of such travel effective in perceptibly resisting actuation of the trigger. Thus, the chances of the sear being jarred olf the cocking-corner of the hammer are greatly reduced, if not entirely eliminated, by the safety surface of the present invention. At the same time, since the relative movement between the sear and cockingcorner can not be detected by the shooter when the cocking-corner engages the safety surface, there is no movement of the sear which is perceptible to the shooter because the amount that the sear must move while the cocking-corner is in contact with the latching surface behind the apex of the safety angle is so small that it can not be felt.

In order to illustrate the principles of the invention still further, an example will be given of specific angles and dimensions within manufacturing tolerances of the latching and safety surfaces which have been found to provide highly satisfactory results in the type of ring mechanism hereinbefore specifically described. Thus, the

latching surface 64 may be disposed at an angle to the direction of the force F such that angle X is equal to approximately 83, while the angle Y between safety surface 62 and the plane of latching surface 64 is equal to about making the angle Z between safety surface 62 and force F in the vicinity of 87. It should be noted here that due to rotational movement of sear 32 in this particular type of tiring mechanism, the angle of safety surface 62 to force F changes slightly when cockingcorner l2 engages surface 62. Such change, however, is always in a direction which will reduce the tendency for the cooking-corner to slip off the sear. When the scar is in its full-cooking position, as shown in full lines in FIG. 3, the effective sear travel, so-called, or distance from the cooking-corner 42 to the apex A of the safety angle is from 0.003 to 0.004 'of an inch. The distance from the apex A to the release point B along safety surface 62 is in this instance a maximum of 0.009 of an inch. The over-all Sear travel is, therefore, approximately twelve or thirteen thousandths of an inch, While the effective sear travel insofar as the action of the trigger is concerned is only about one fourth of the total Sear travel.

In this connection, it is of interest to note that a gun in which the sear travel is two or three thousandths of an inch is considered to be dangerous, even though it may be manufactured with the greatest care and be provided with the usual safety devices, such as the safety notch on the hammer. Ordinarily, however, at least four to six thousandths of an inch sear travel is provided. Consequently, the present invention provides even greater actual sear travel than is normally provided and, therefore, provides a gun which is even safer than most without the expected trigger creep which has heretofore characterized guns considered to be safe. A gun incorporating the hereinabove described tiring mechanism, and having substantially the speciiic dimensions and angles of the scar engagement mentioned, has a trigger pull of only two pounds as compared to other guns which have a comparable degree of safety requiring at least three or four pounds trigger pull.

Although it has been mentioned hereinabove that the angie Y between the safety surface 62 and the plane of latching surface 64 is equal to about 10 or 20, it is believed to be practical to reduce this angle to only about 5, if desired, or to make it as large as 30 or more. It will also be noted that in the specific example given above the force exerted by the hammer on the sear is not exactly perpendicular to the safety surface when the cooking corner of the hammer engages this surface. The arrangement in this case is such that the force of the hammer actually tends to urge the sear against the sear spring, which therefore lightens the force required to retract the sear. On the other hand, the latching surface is so disposed that the hammer must be slightly depressed against the urge of the hammer spring so that a much greater force is required to retract the sear than is the case when the cooking corner contacts the safety surface. It will be appreciated, however, that the safety surface could be disposed perpendicular to the direction of the force exerted by the hammer on it, if desired. Moreover, if the latching surface were disposed at a sharper angie X with respect to the cooking corner, providing a relatively heavy trigger pull, the angle Z to the safety surface might even be greater than 90 s0 long as the torque required to retract the sear at this point is substantially less than that required when the latching surface engages the cooking corner of the hammer.

in determining the length of the safety surface 62 or distance between the points A and B in FIG. 3, the maximum amount of deviation of Sear 32 from its fullcocking position should be determined under various conditions of shock to which thegun may be subjected, as for example in case it is dropped. The safety surface may then be made to allow for the worst condition Vwhich may be expected, so that the Sear can not jump beyond the edge of the safety surface, but will come to rest momentarily with the cooking-corner on the safety surface. It will be understood, however, that the cookingcorner does not remain in engagement with the safety surface because, as has been brought out hereinabove, that surface is so arranged that the resultant of the forces acting on the sear under such conditions will cause it to return immediately to its full-cooking position.

The term static condition, as used herein in connection with the conditions wherein the cooking-abutment engages the safety surface, refers to the instant at which the sear comes to rest after it has been jarred from latching-surface engagement by an external blow on the fgun. Such static condition may be likened to ya hypothetical situation in which the sear is physically' set in such a position that the safety surface engages the cocking-abutment and then is released.

A further advantage of the invention which should be mentioned here is that, due to the provision of the safety surface, the gun will not become unsafe in case the corner |42 of Sear notch 3S becomes vrounded oi slightly because of wear. Thus, so long as the point of engagement of corner 42 is behind the apex A of the safety angle, the hammer 18 can not fall oif the sear accidentally. In conventional Sear engagements, however, if due to wear the point of engagement of the cooking-corner on the hammer becomes as little as one or two thousandths of an inch from the release point on the sear, there will be serious danger of accidental firing of the gun. Moreover, by providing the safety surface of the present invention, the corner 4Z on the hammer can be purposely made to engage the latching surface 64 within only one or two thousandths of yan inch of the apex A of the safetyangle without making the gun unsafe, thereby obtaining the advantage of a hair-trigger in eliminating creep.

While the hereinabove-described example of one particularly desirable embodiment of the invention contemplates provision of the so-called safetyand latching surfacesV as being located on the sear, it will be understood that one or both of said surfaces could be formed on the firing member instead of on the sear. Such modications therefore come within the scope of the present invention as defined by the appended claims.

What is claimed is:

l. In a tiring mechanism having a ring member, a sear member movable into and out of cooking engagement with said firing member, a spring for operating said tiring member, lspring-means for resiliently uring said Sear member into engagement with said tiring member, and trigger means for positively moving said sear member against the resilient force of said spring-means out of said cooking engagement; the improvement in the interengagement of said sear member with said tiring member comprising a latching surface on one of said members engageable with a portion of the other of said members when said Sear is in its full-cooking position, said latching surface forming an angle with the direction of the force exerted on said Sear member by said tiring member which requires a substantially normal trigger pull in order to move said sear member out of said fullcocking position, and a safety surface on one of said members disposed at an angle` with said latching surface and located so as to be engaged by a portion of the other of said members upon movement of said sear member a predetermined distance from said full-cocking position, said safety and latching surfaces being substantially ilat and disposed so that said firing member is held in cocked position by engagement of either of said surfaces, said safety surface forming an angle with respect to the direction of said force on said sear member such that thertrigger pull required to move said -sear member out of said cooking engagement when said safety surface is 7 engaged by the other member is negligible compared to said normal trigger pull.

2. In a ring mechanism, a tiring member having a cooking-abutment, a sear movable into and out of engagement with said cooking-abutment, a spring for operating said ring member, spring-means for resiliently urging said Sear into engagement with said firing member, and `trigger means for positively moving said sear out of engagement with said cooking-abutment against the resilient force of said spring-means; the improvement comprising a latching surface on said sear engageable with said cooking-abutment When said lsear is in its fullcocking position, and a safety surface on said sear located between said latching surface and the actual release point on said Sear, said latching and safety surfaces each being substantially at and disposed at an angle to the direction of the force exerted by said cocking-abutment on said sear such that said spring-means will move said sear into said fu'll-cocking position whenever under static conditions said cooking-abutment engages Said scar at any location between said full-cocking position and said actual release point; said safety surface being disposed at a different angie to the direction of said force exerted by said cooking-abutment from that of said latcliing surface, said surfaces being contiguous and forming an abrupt angle at their intersection such that, whenever said trigger means is manipulated so as to move said sear from said full-cooking position bringing said safety surface into engagement with said cocliing-abutmen-t, said spring-means is incapable of preventing release of said tiring member.

3. In a tiring mechanism, a firing member having a cooking-abutment, a sear movable into and out of engagement with said cocking-abutment, a spring for operating said ring member, spring-means for resiliently urging said sear into engagement with said cookingabutment and trigger means for positively moving said sear out of engagement with said firing member against the resilient force of said spring-means; 'the improvement comprising a latchirrg surface on said sear engageable with said cocking-abutment when said sear is in its fullcocking position and a safety surface on said sear contiguous with and forming an abrupt angle with said latching surface, said safety surface being located so as to be engaged by said cocking-abutment upon movement of said sear from its full-cocking position, said safety and latching surfaces being substantially flat and disposed so that said ring member is held in cocked position by engagement of either of said surfaces, said safety surface being disposed rellative to said cooking-abutment such that the trigger pull required to move said Sear when said cookingabutment engages said safety surface is substantially less than the trigger pull required to move said Sear when said cooking-abutment engages said latching surface.

4. In a ring mechanism, the impro-vement deiined in claim 3, wherein the angle between said safety surface and the plane of said latching surfaces is equal to from 10 to 20.

References Cited in the file of this patent UNITED STATES PATENTS 402,423 Ehbets Apr. 30, 1889 2,143,028 Pike Ian. 10, 1939 2,331,405 Loomis Oct. 12, 1943 2,462,585 Wesson Feb. 22, 1949 2,775,836 Emerson Jan. 1, 1957

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