US2558871A

US2558871A - Trigger mechanism

Info

Publication number: US2558871A
Application number: US11110A
Authority: US
Inventors: Elmer E Miller
Original assignee: Individual
Current assignee: Individual
Priority date: 1948-02-26
Filing date: 1948-02-26
Publication date: 1951-07-03
Anticipated expiration: 1968-07-03

Description

July 3, 1951 E. E. MILLER TRIGGER MECHANISM Filed Feb. 26; 1948 INVENTOR.

3 Sheets-Sheet 1' m I E mm W E v B%M$%M '/1 IS ATTORNEYS E. E. MILLER TRIGGER MECHANISM July 3, 1951 Filed Feb. 26. 1948 v 9 v v By y 3,1951 y E. E.- MILLER 2,558,871

' TRIGGER MECHANISM Filed Feb. 26. 1948 3 Sheets-Sheet 5 'INVENTOILLY .ELM R EM LLER ATTORNfYS Patented July 3, 1951 ATENT OFFICE This invention relates to a trigger mechanism for a gun.

An important object of this invention is to provide a trigger mechanism in which, when the gun is cooked, a force is normally applied tending to disengage the sear from the hammer, with a latch engaging the sear to oppose the force and prevent disengagement of the sear from the hammer. Instead of using trigger pressure to force the sear out of a notch on the hammer, one of the features of the present invention resides in the arrangement of the engaging portions of the sear and hammer so that the hammer spring, acting through the hammer, tends to force the sear away from the hammer. A latch engages the sear to prevent release of the hammer until the latch is disengaged from the sear by pulling the trigger.

' Another important object of the present invention is to providea trigger mechanism with an adjustment for varying the trigger pull necessary to fire the gun. This is accomplished according to a feature of the invention whereby the relative positions of the sear and the sear latch may be changed at will to vary the resistance which must be overcome to disengage the latch from the sear. This adjustment of the latch may be accomplished by moving a lever which extends through the breech frame. It is, therefore, a specific object of the invention to provide a trigger pull adjustment which may be effected without dismantling the gun.

' Other objects of the invention will become apparent from the following specification taken in connection with the accompanying drawings wherein Figure 1 is a side view of a trigger mechanism embodying the invention, some parts being broken away and others being shown in section for purposes of clearness, the mechanism being shown with parts in the positions assumed when the gun is cooked;

Fig. 2 is a horizontal section taken on the line 2-2 of Fig. 1;

Fig. 3 is a partial vertical section similar to Fig. 1 but showing the positions of the parts after the gun is fired;

Fig- 4 is an enlarged fragmentary view showing the sear latch and its related parts;

Fig. 5 is a sectional view showing one arrangement for cocking the gun;

Fig. 6 is a partial view of the trigger mechanism as seen from the side opposite to that shown in Fig. 1;

Fig. 7 is a cross-sectional view taken on the line 1-4 of Fig. 1;

Fig. 8 is a partial sectional view taken on the line 8-8 of Fig. 6;

Fig. 9 is a partial sectional view taken on the Fig. 13 is a plan view of the adjustable latch:

support.

According to the invention in its preferred form, a hammer is pivoted in the usual fashion in a breech frame and a sear pivoted in the breech frame is arranged to engage an abutment on the hammer to hold the hammer in cocked position against the force applied by the hammer spring. The engaging portion of the sear has a cam surface cooperating with the abutment on the hammer so a force is applied tending to disengage the sear from the hammer. To hold the sear engaged with the abutment, a latch is arranged to engage a notch formed on the sear. This latch is carried by a latch member pivoted to an adjustable latch support secured to the frame but provided with an adjustable device for changing the position of the latch relative to the notch. The latch member has a cam for engaging a trigger pivoted on the frame so operation of the trigger turns the latch member about its pivot thereby releasing the latch from the notch. When the latch is disengaged from the notch, the cam on the sear cooperates with a cam surface on the hammer so the sear is moved away from the latch to prevent re-engagement until the hammer is again cocked.

The trigger pull necessary to fire the gun is adjustable by changing the relative angular positions of the latch and the notch. In the preferred form of the invention, this adjustment is accomplished by turning the latch in the latch member. A lever onthe latch extends through the frame adjacent the trigger for turning the latch to adjust the trigger pull Without dis mantling the gun.

Referring now to the drawings for a detailed description of the embodiment of the invention shown therein, a breech frame 2| is shown as having a lower tang 22 extending rearwardly from the lower part of the frame. A hammer 23 is carried by a pivot 24 mounted on the frame 21, and a hammer spring 25, arranged in a housing 26 formed as a part of the frame, presses mer 23 about the pivot 24 until the hammer reaches its cocked position.

Usually, the hammer of a gun of this type is I held in its cocked position by a sear which is ar-' ranged to engage a notch in the gun. ,The' engaging portions of the scar and the notch are ordinarily shaped so the pressure applied by the hammer spring exerts a force on the hammer tending to hold the sear in the notch. According to an important feature of the present invention, a sear 35 is carried by a pivot 36,1nounted in the frame 2! so its forwardly -projecting end portion 31 will engage an abutment 38 on the hammer. The engaging part of the sear is formed with a cam surface 39 sloping upwardly and rearwardly from the hammer so it tendsto disengage itself from the abutment 33 on the hammer. In other words, the hammer spring25 exerts a force through the hammer so the pressure applied by the abutment 38 on the cam surface 39 tends to force the cam surface 39 and the forwardly projecting end portion 3'! away from the hammer.

To hold the cam surface39 on the sear in gagement with the abutment 32 to retain the hammer in its cocked position, a rearwardly extending portion 4! of the sear 35 is engaged by a latch 42. Latch 42 is in the form of a wedge shaped projection extending laterally from a latch member 43 supported on the lower tang 22 of the frame by a pivot 44- which extends between rearwardly extending

arms

45, 45, of an adjustable latch support 46 (Fig. 13) having its forward end 41 secured to the lower tang 22, as by a bolt 48. The latch member 43 has an ear 49 formed at the rear end of its lower side for engaging the rear portion of an upper surface on a trigger 52. The trigger is mounted on a pivot 53 carried by

projections

54, 54, (Fig. 11) extending upwardly from the tang 22 through an opening 55 formed in the latch support 45. An opening 59 is provided in the tang 22 to permit the trigger finger to extend below the tang in the usual fashion.

Positive engagement of the latch 42 with the sear 35 is accomplished by an enlarged portion 56 on the rearwardly extending portion 4| of the sear 35. As shown most clearly in Fig. 12, this enlarged portion extends laterally from the sear toward the latch 42 and is formed with a notch 51 arranged to engage with the latch 42.

When the hammer is cooked by rearward movement of the rod 32, a leaf spring 58 secured by the bolt 48 to the lower tang 22 presses against the lower edge of the forwardly extending portion 31 of the sear to force the cam surface 39 into a recessed portion 59 of the hammer behind the abutment 38. Inasmuch as the hammer is moved slightly counter-clockwise from its cocked position, as shown in Fig. 1, the forward upper lip 6| of the notch 51 is moved below the position of the latch 42 so the latch can engage in the notch 51. To insure movement of the latch into the notch, a coiled wire spring 62 (Fig. 6) has one end secured by a bolt 63 to the side of. th

latch member 43 and its other end projecting forwardly so it lies in a channel 64 formed in the upper surface of a weight 65 secured by a bolt 65 to the portion of the trigger 52 in front of its pivot 53. The coil of the spring 62 is so arranged that it tends to turn the latch member 43 clockwise about the pivot 44, as shown in Fig. 6, or counter-clockwise, as shown in Fig. 1. When the latch 42 engages the notch 51, release of the cocking pressure on the rod 32 permits the hammer to be moved (clockwise as shown in Fig. 1) by the hammer spring to the position shown in Fig. 1 with the cam surface 39 on the sear in engagement with the abutment 38 on the hammer. Although the cam surface 39 tends to disengage .the sear from the abutment, such movement is prevented by engagement of the latch 42 in the notch, .51 on the other end of the sear. When it is desired to fire the gun, pressure is applied to the-trigger 52 turning it about its pivot 53' so its rear surface 5! moves upwardly raising the ear .49 on the latch member 43. This upward movement of the ear 49 turns the latch member 43 about its pivot 44 so the latch 42 is moved forwardly with respect to the sear and becomes disengaged from the notch 51. Upon disengagement of the latch from the notch, the sear is released and the cam surface 39 is disengaged 1 from the abutment 33 so the hammer is released to fire the gun. As the hammer moves toward the firing pin 29, the cam 39 on the sear engages a cam surface 61 extending around the hammer from the abutment 38. This cam surface turns the sear clockwise about its pivot 36, as shown in Fig. L thereby raising the rearwardly extending portion 4| of the sear so, when the trigger 52 is released, the latch 42 engages the sloping front portion 68 of the projection 55 in front of the notch 51, as shown in Fig. 3. This holds the latch in position to return into engagement with the notch when the sear is permitted to move by returning the hammer to its cocked position.

The latch 42 is arranged on the latch member 43 directly above the pivot 44, so the latch 42 moves approximately parallel to the lower tang 22 when the latch member is turned by pulling Inasmuch as the under side 69 of" the trigger. the latch 42 slopes forwardly and upwardly, beforethe latch 42 can be moved to release the sear, it must force the rear portion 4| of the sear downwardly as it moves over the lip 6| of the notch. The downward movement of the sear is permitted by the resiliency of the sear itself so the elasticity of the sear determines the resistance between the under surface 69 on latch 42 and the forward lip Bl of notch 51, which must be overcome by pressure on the trigger 52 in order to fire the gun. Obviously, the further the rear portion of the sear must be depressed the greater the force which must be applied to the trigger before the gun is fired.

This characteristic of the trigger mechanism is utilized to provide an adjustment of the trigger pull, that is, an adjustment whereby the trigger pressure necessary to fire the gun may be increased or decreased as desired. To this end, the latch member 42, as shown most clearly in Fig. 10, projects from a cylindrical latch bearing H which may be inserted into an aperture 12 formed in the upper portion of the latch member 43. The latch bearing 1| rests against a shoulder [3 in the aperture so it may be turned in the latch member thereby turning the latch 42 and changing the angular position of its under sure 69 h respect to t e forward lip 6| of the notch 51. To facilitate turning the latch in the latch member, the latch bearing "H is provided with a projection M extending through the aperture 12 to the side of the latch member 43 opposite that on which the latch -42 is arranged. In order that the latch 42 may be turned in the latch member 43 without dismantling the gun, a lever plate 1.5 (Fig. 6) is provided with a rectangular opening fitting around the projection 14 and held in position on the latch by a pin 18. The lever plate 15 extends downwardly and is provided with an adjustment lever H5 which extends through the slot 56 which accommodates the trigger 52 in the lower tang 22. To permit the plate 15 to be moved by the lever 15 to turn the latch 42, the plate 15 has an arcuate opening T! to accommodate the pivot 44 for the latch plate. The ends of this opening serve as limits to prevent excessive movement of the lever plate 15.

By moving the adjustment lever I6 forwardly along the opening 552 in the tang 22 the latch bearing 11' is turned counter-clockwise, as shown in Fig. 1, to increase the inclination of the under side 59 on the latch 42. As this angular inclination of the under side 69 on the latch 42 is increased, the pull necessary to release the latch from the notch on the ear is correspondingly increased, because it is necessary to depress the rear portion 4| of the sear further when the latch 42 is in the position shown in Fig. 4 than the depression necessary when the latch is in the position shown in Fig. l. tor increasing the trigger pull is the reduction in the mechanical advantage as the angular inclination of the latch is increased. When the latch is in its position as shown in Fig. 1, only a slight pull is necessary to move the latch forwardly so the sear rides down the slightly sloping under side 59. When the pitch of the latch is increased, as shown in Fig. 4, a greater pull is necessary to move the latch upwardly, because a greater force is necessary to move the forward lip Bl downwardly along the steeper slope of the under side 69.

Any desired trigger pull, within certain minimum and maximum limits may be obtained by placing the lever 16 at a selected point between its position of minimum pull, as shown in Fig. l, and its position of maximum pull, as shown in Fig. 4. is available to the user of the gun depending upon the position at which the lever 76 is set. A particular advantage of this mechanism resides in the provision of a trigger pull adjustment which may be effected without dismantling the gun.

As previously mentioned, the adjustable latch support 46 is secured at its forward end by a bolt 48. The latch support 45 is made of resilient material such as spring steel so it tends to raise its rearwardly extending members 45 which support the latch member 43. The position to which the members 45 are raised may be determined by a bolt 8! which extends upwardly through the trigger opening 50 in the tang 22 and is screwed into a tapped opening 82 in rear portion 83 of the latch support 48 connected to rearwardly extending members 5. The head of the bolt 8! engages the under side of the tang 22, as shown most clearly in Fig. 8. By turning the bolt 8! the amount which the latch support is raised above the tang may be determined by the distance from the head of the bolt 8! to the rear portion 83 of the latch support. The effect of this raising or lowering of the latch support is to adjust the longitudinal alinement of the latch42 Another fac- Thus, either a light or a heavy trigger with the notch 51. Inasmuch as the distance from the latch member pivot 44 to the point to which latch support is is fixed to the tang 22 is somewhat less than the distance from the notch 51 to the sear pivot 36, adjustment of the bolt 8| moves the latch 42 about a somewhat shorter arc than the arc through which the notch of the sear is moved. Thus, when the latch support is moved downwardly, the latch 52 is moved forwardly with respect to the corresponding position of the notch on the sear. The latch 42 may thus be adjusted longitudinally of the gun so it will fit into the notch or will merely engage a portion of the forward wall of the notch. In other words, the point at which the forward lip 6! of the notch engages the under surface 69 on the latch may be adjusted to increase or decrease the distance from that point to the edge of the wedge shaped latch. mine the distance through which the trigger must be pulled to release the latch, adjustment of the latch support serves to vary the amount of free trigger, that is, the distance through which the trigger must be pulled to fire the gun.

In operation, with the gun uncooked, as shown in Fig. 3, cocking pressure applied to cocking cam 33 is permitted through rod 32 to move the hammer 22% counterclockwise (Fig. 3) until cam surface 33 on the sear 35 moves into recess 59 behind an abutment 33 on the hammer. When the sear is moved into the recess 38 by leaf spring 58, the sloping front portion 68 of the enlarged rear end of the sear moves latch 42 upwardly about its pivot id until the latch can pass over forward lip 6! of the notch. 57. At this time, re lease of cooking pressure permits the hammer to move clockwise (Fig. 1) so the cam surface 39 engages abutment 3-3. Although the cam surface 39 is so shaped that it tends to disengage itself from the abutment 38, latch 42 prevents movement of the sear away from the hammer until the trigger 52 is pulled to lift the ear 49 on the latch member 43 and thereby move the latch 42 forwardly to release the sear.

The distance through which the trigger must be pulled before the gun is fired depends upon the distance from the forward lip 61 of the notch 51 to the edge of the latch 42, that is, the distance which the forward lip slides along the slop- This distance may be 'in-,

mg under surface 69. creased by raising the latch support 46, or decreased by turning bolt 8| to lower the latch support relative to the tang 22. Once the correct position is attained, the bolt 8! may be locked by engagement of the head on an adjoining bolt 84 with an arcuate notch 85 formed in the head of the bolt 8|.

The trigger pull necessary to fire the gun may be varied by moving the adjustment lever 16. To increase the trigger pull, the adjustment lever 16 is moved forwardly thereby turning latch bearing H to increase the angle of inclination of the under side 69 on the latch 42. This change in the angular inclination of the latch reduces the mechanical advantage of the mechanism by which pressure on the trigger releases the sear and also increases the distance which the sear must be depressed before it is released from the latch 42. As the lever #6 projects through an enlargement 86 of the trigger opening 513 in the lower tang 22, the trigger pull may be varied without dismantling the gun.

What is claimed is:

1. In a trigger mechanism for a gun, a sear pivoted intermediate its ends having one end for As this distance deter engaging an abutment on a hammer to hold the hammer in cocked position, the other end of said sear being formed with a notch, and a sear latch adjacent said other end of the sear for engaging said notch to hold said one end of the sear engaged with the abutment on the hammer, said sear latch being operable by a trigger to release said sear for firing the gun, and means independent of the trigger for adjusting said sear latch to change its angular position relative to said notch and thereby vary the trigger pull necessary to operate said latch and release the sear to fire the gun.

2. In a trigger mechanism for a gun, a sear pivoted intermediate its ends having one end for engaging an abutment on a hammer to hold the hammer in cocked position, the other end of said sear being formed with a notch, a latch support movable toward and away from said sear, a sear latch on said adjustable latch support adjacent the other end of said sear for engaging said notch to hold said one end of the sear engaged with the abutment on the hammer, said sear latch being operable by a trigger to release said sear for firing the gun, and means independent of the trigger for moving said latch support to change the position of said sear latch relative to said notch.

3. In a trigger mechanism for a gun, a sear pivoted intermediate its ends having one end for engaging an abutment on a hammer to hold the hammer in cocked position, the other end of said sear being formed with a notch, a movable latch support adjustable toward and away from said sear, and a sear latch on said adjustable latch support adjacent said other end of the sear for engaging said notch to hold said one end of the sear engaged with the abutment on the hammer, said sear latch being operable by a trigger to release said sear for firing the gun, said sear latch being adjustably movable on said latch support in a manner such that movement of said sear latch relative to said latch support changes the angular position of said latch relative to said notch.

4. In a trigger mechanism for a gun, a sear pivoted intermediate its ends having a cam sur face at one end for engaging an abutment on a hammer to hold the hammer in cocked position, said cam surface being shaped so it tends to disengage itself from the abutment on the hammer, the other end of said sear being formed with a notch, and a sear latch adjacent said other end of the sear for engaging said notch to hold said cam surface engaged with the abutment on the hammer, said sear latch being operable by a trigger to release said sear for firing the gun, said latch being rotatably adjustable about a transverse axis to vary its angular position relative to said notch and thereby vary the trigger pull necessary to operate said latch and release the sear to fire the gun.

5. In a trigger action for a gun having a hammer, a sear therefor and a trigger, a trigger pull adjustment mechanism comprising a pivoted latch carrying member operable by the trigger, and a latch on said member extending transversely therefrom for engaging the sear to hold it in cocked position, said latch being adjustably mounted on said latch member to change its angular position relative to the sear and thereby vary the trigger pull necessary to operate said latch member and release the sear to fire the gun.

6. In a trigger action for a gun having a hammer, a sear therefor and a trigger, a trigger pull adjustment mechanism comprising a pivoted latch carrying member operable by the trigger,

vary the trigger pull necessary to operate said latch member and release the sear to fire the gun.

7. In a trigger action for a gun having a hammer,,a sear therefor and a trigger, a trigger pull adjustment mechanism comprising a pivoted latch carrying member operable by the trigger, and a wedge shaped latch extending transversely from said member for engaging a notch in the sear to hold it in cocked position, said latch being turnable on said member about a transverse axis to adjust its angular position with respect to said notch and thereby change the trigger pull necessary to operate said latch member and disengage said latch from the notch to release the scar and fire the gun.

8. A trigger mechanism for a gun comprising,

a frame, a scar pivoted in said frame, a trigger pivoted in said frame, a latch carrying member adjacent one end of said sear pivotally mounted on said frame above said trigger and movable thereby, and a latch projecting from said member to engage a notch formed in said sear to hold the other end of said sear engaged with a hammer when in cocked position and releasable by operation of said trigger, said latch being movably mounted on said latch member in a manner such that movement of said latch relative to said member changes the angular position of said latch with respect to said notch and thereby ad justs the trigger pull necessary to release said latch from said notch.

9. A trigger mechanism for a gun comprising a frame, a sear pivoted in said frame, a trigger pivoted in said frame, a latch carrying member pivotally mounted on said frame above said trigger adjacent one end of said sear, a latch projecting laterally from and movably mounted on said member to engage a notch formed in said sear to hold the other end of said sear engaged with a hammer when in cocked position, said latch member being movable about its pivot by operation of said trigger thereby releasing said notch from said latch, said latch being movably mounted on said latch member in a manner such that movement of said latch relative to said member changes the angular position of said latch relative to said notch, and a lever on said latch extending through said frame adjacent said trigger for moving said latch to adjust the angular position relative to said notch and thereby change the pull on said trigger necessary to operate said latch member and release the sear to fire the gun.

10. A trigger mechanism for a gun comprising a frame, a hammer mounted on a pivot in said frame, a sear pivoted intermediate its ends to said frame, having a cam surface on one end arranged to engage an abutment on said hammer to hold said hammer in cocked position, said cam surface being so shaped that it tends to disengage itself from said abutment, a latch carrying member in engagement with said abutment, said latch member being operable by a trigger, and a latch projecting transversely from said member for engaging the other end of said sear to retain said cam surface in engagement with said abutment, said latch being mounted on said member to turn about a transverse axis for adjusting the angular position of said latch relative to said other end of the sear and thereby change the trigger pull necessary to operate said latch member and release the latch from the sear to fire the gun.

11. A trigger mechanism for a gun comprising a, frame, a hammer mounted on a pivot in said frame, a scar pivoted intermediate its ends to said frame having one end arranged to engage an abutment to hold said hammer in cocked position and the other end formed with a notch, a latch carrying member pivoted on said frame adjacent said other end of said sear and operable by a trigger, and a latch turnable about a transverse axis on said latch member and projecting transversely from said latch member for engaging said notch to retain said one end in engagement with said abutment, the trigger pull necessary to release the sear being adjustable by turning said latch to adjust its angular position relative to said notch.

12. A trigger mechanism for a guncomprising a frame, a hammer mounted on a pivot in said frame, a sear pivoted to said frame having one end arranged to engage an abutment to hold said hammer in cocked position and the other end formed with a notch, a latch carrying member pivoted on said frame adjacent said other end of said sear, a latch turnable about a transverse axis and projecting transverse from said latch member for engaging said notch to retain said one end in engagement with said abutment, said latch member being operable by a trigger for releasing said latch from the notch on the sear to fire the gun, and a lever on said latch extending through said frame for turning said latch to adjust the angular position thereof relative to said notch and thereby vary the trigger pull necessary to operate said latch member and fire the gun.

13. In a trigger action for a gun having a hammer, a sear therefor and a trigger, a trigger pull adjustment mechanism comprising a latch support movable toward and away from the sear, a latch carrying member pivoted on said support and operable by the trigger, and a wedge shaped latch extending transversely from said member for engaging a notch in the sear to hold it in cocked position, said latch being turnable about a transverse axis on said latch carrying member to adjust the angular position of said latch relative to the scar and thereby change the trigger pull necessary to operate said latch ,carrying member and disengage said latch from the notch to release the sear and fire the gun, movement of said latch support serving to adjust the position of said latch relative to the notch in the sear.

14. In a trigger action for a gun having a hammer, a sear therefor and a trigger, a trigger pull adjustment mechanism comprising a pivoted latch carrying member operable by the trigger, a latch on said member extending transversely therefrom for engaging the sear to hold it in cocked position, and means for turning said latch about a transverse axis on said member to change the angular position of said latch relative to the sear and thereby vary the trigger pull necessary to operate said latch member and release the sear to fire the gun.

15. In a trigger action for a gun having a hammer, a sear therefor and a trigger, a trigger pull adjustment mechanism comprising a pivoted latch carrying member operable by the trigger, a Wedge shaped latch extending transversely from said member for engaging a notch in the sear to hold it in cocked position, and means for turning said latch about a transverse axis on said member to adjust the angular position of said latch with respect to said notch and thereby change the trigger pull necessary to operate said latch carrying member and disengage said latch from the notch to release the sear and fire the gun.

16. In a trigger action for a gun having a hammer, a scar therefor and a trigger, a trigger pull adjustment mechanism comprising a latch support movable toward and away from the sear, a latch carrying member pivoted on said support and operable by the trigger, a wedge shaped latch extending transversely from said member for engaging a notch in the sear to hold it in cocked position, means for turning said latch about a transverse axis on said latch carrying member to adjust the angular position of said latch relative to said notch and thereby change the trigger pull necessary to operate said latch carrying member and disengage said latch from the notch to release the sear and fire the gun, and means for moving said latch support relative to the sear for adjusting the position of said latch relative to the notch in the sear.

ELMER E. MILLER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS FoREiGN PATENTS Country Date Great Britain Aug. 25, 1939 Great Britain Apr. 14, 1943 Number Number