US3577827A

US3577827A - Trigger mechanism

Info

Publication number: US3577827A
Application number: US793958*A
Authority: US
Inventors: William J Billett; Edwin S Vartanian
Original assignee: Olin Corp
Current assignee: US REPEATING ARMS COMPANY Inc
Priority date: 1969-01-27
Filing date: 1969-01-27
Publication date: 1971-05-04
Anticipated expiration: 1988-05-04

Abstract

A trigger mechanism for a semiautomatic firearm having a reciprocating bolt assembly, the mechanism having a trigger member which is releasably connected to a sear member. The trigger member is disconnected from the sear by reciprocation of the bolt assembly or by actuation of a safety. Means are provided for adjusting the trigger pull and for retaining the preset trigger pull against maladjustment.

Description

United States Patent [72] Inventors William J. Billett Fairrnont, Minn.; Edwin S. Vartanian, North Haven, Conn. [21 1 Appl. No. 793,958 [22] Filed Jan. 27, 1969 [45] Patented May 4, 1 971 [73] Assignee Olin Matltieson Chemical Corporation [54] TRIGGER MECHANISM l 1 Claims, 7 Drawing Figs.

[52] US. Cl 89/145, 89/148 [51] Int. Cl F4lc 19/00 [50] Field of Search 42/69 (A,B);89/l40l50 [56] References Cited UNITED STATES PATENTS 1,997,954 4/1935 VonFrommer 42/698 Primary Examiner--Benjamin A. Borchelt Assistant Examiner-Stephen C. Bentley Attorneys-H. Samuel Kieser, Donald R. Motsko, William W. Jones, Richard S. Strickler, Robert H. Bachman, Donald R. Motsko and Thomas P. ODay ABSTRACT: A trigger mechanism for a semiautomatic" firearm having a reciprocating bolt assembly, the mechanism having a trigger member which is releasably connected to a sear member. The trigger member is disconnected from the sear by reciprocation of the bolt assembly or by actuation of a safety. Means are provided for adjusting the trigger pull and for retaining the preset trigger pull against maladjustment.

4 Sheets-Sheet 1 INVENTORSI EDWIN $.VART4NIAN WILLIAM J. BILLET BY WM 00.2w

ATTORNEY Patented May 4, 1971 4 Sheets-Sheet 2 INVENTORS' EDWIN S. VARTAN/AN WILLIAM J. BILLET BY 404;...- M),

ATTORNEY Patente d May 4, 1971 3,577,827

4 Sheets-Sheet ,5

ATTORNEY TRIGGER MECHANISM This invention relates to a trigger mechanism for use with a bolt action, semiautomatic firearm, wherein the trigger is only connected to the sear when the bolt is locked in its battery position. When the bolt is moved out of its battery position, and toward its retired position, the trigger is automatically disconnected from the sear. The trigger is then free to more independently of the sear.

In bolt action, semiautomatic, self-loading firearms, a reliable mechanism is needed for disconnecting the trigger from the sear after the weapon is fired in order to allow the sear to reengage the hammer and prevent full automatic firing from accidentally occuring. Not only is it advantageous to disconnect the trigger from the sear after the weapon has been fired, it is also desireable that the trigger remain disconnected from the sear until the bolt is locked in its battery position. This eliminates the chance that the weapon can be fired accidentally while the bolt is not locked in its battery position, and this also eliminates the disconcerting occurrence of having the hammer fall by pulling the trigger when the bolt is unlocked even though other safety features prevent the weapon from firing in this condition.

It is also desirable, when firing a semiautomatic weapon, to eliminate preliminary trigger take up which occurs before the gun is fired. The phrase preliminary trigger takeup" refers to the initial movement of the trigger which occurs when the latter is pulled, and which initial movement does not result in disengagement of the sear from the hammer. This trigger take up impairs the accuracy of the shooter since it results in a delay between aiming and firing, during which delay the aiming of the gun must be maintained steadily. By eliminating trigger takeup, pressure exerted on the trigger is immediately utilized to disengage the sear from the hammer.

The mechanism of this invention includes a trigger which is connected to a hammer sear when the bolt assembly is locked in its battery position, but which is disconnected from the hammer sear when the bolt is in its reciprocation cycle. The trigger is formed in a unitary piece which is pivotally mounted for, and biased into, engagement with a connector element. The connector is movable into and out of contact with the hammer sear, so that when the connector contacts the sear, movement of the trigger is transferred to the sear through the connector. A disconnector member is arranged for contact with the connector; the disconnector being capable of moving the connector out of engagement with the sear. This latter operation is accomplished during reciprocation of the bolt assembly.

The mechanism of this invention also includes safety means which are operable to prevent firing of the weapon when the bolt is locked in its battery position and the hammer is cocked. The safety performs the dual function of positively locking the sear into engagement with the hammer, and also moving the connector out of engagement with the sear. Thus, when the safety is on, the trigger is disconnected from the sear so that accidental pulling of the trigger will not apply force to the sear and the sear is locked against the hammer so that even jostling of the gun will not result in an accidental firing.

Adjustment of the trigger pull force necessary to disengage the sear from the hammer is accomplished by means of an adjustment screw which bears against a spring which, in turn, bears against the sear. Adjustment of the screw varies the spring force directed against the sear resulting in a varying of the force with which the sear is moved against the hammer. When the trigger housing is mounted in the firearm receiver, the adjustment screw is held against rotation by positive engagement with the receiver so that the preadjusted trigger pull force will not vary as the gun is fired.

It is, therefore, an object of this invention to provide a trigger assembly for use with a semiautomatic, bolt-actuated firearm, wherein the trigger can be connected to a hammer sear only when the bolt is locked in its battery position.

It is a further object of this invention to provide a trigger assembly of the character described having a connector element movable into and out of engagement with the sear.

It is yet another object of this invention to provide a trigger assembly of the character described wherein the trigger is biased at all times into engagement with the connector.

It is still another object of this invention to provide a trigger assembly of the character described having a disconnector member operable to move the connector out of engagement with the sear when the bolt is reciprocated.

It is a further object of this invention to provide a trigger assembly of the character described having a safety actuable to disengage the connector from the sear.

It is a further objective of this invention to provide a triggersear assembly which moves as a solid unit with no relative motion between the trigger, connector or sear during the trigger pull cycle and thus giving the sensation of crispness" to the shooter.

These and other objects and advantages of this invention will become more readily apparent from the following detailed description and accompanying drawings, in which:

FIG. 1 is an exploded view of a preferred embodiment of the trigger assembly of this invention;

FIG. 2 is a side sectional view showing the trigger assembly of FIG. I mounted in a trigger housing and position in a firearm receiver, the various components being shown as they appear when the bolt is locked in its battery position, the hammer is cocked and the safety is off;

FIG. 3 is a fragmentary sectional view taken along line 3-3 of FIG. 2 showing the manner in which the trigger pull adjustment is locked in place in the receiver;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 2 with various parts omitted for clarity, and showing the position of the safety when the latter is off;

FIG. 5 is a sectional view similar to FIG. 2, but showing the manner in which the connector is disengaged from the sear when the bolt is reciprocated; FIG. 6 is a sectional view similar to FIG. 2, but showing the manner in which the safety is operable to disengage the connector from the sear, while at the same time lock the sear into engagement with the hammer; and

FIG. 7 is a sectional view taken along line 7-7 of FIG. 6 with certain parts removed for purposes of clarity.

Referring now to FIG. I, the various components of a preferred embodiment of the trigger assembly of this invention are shown. The assembly includes a unitary trigger member 2 having an aperture 4 to receive a trigger pin 6. The trigger 2 includes a laterally extending flange 8 and a laterally extending lug 10. A connector 12 is disposed adjacent the trigger 2, the connector 12 being formed with a lip 14 and a downwardly extending projection 16. An elongated slot 18 is formed on the connector 12 to receive the trigger pin 6, and the terminal portion of the connector is bent laterally at 20 for reasons more clearly set forth hereinafter. The connector 12 also includes a downwardly dependent protrusion 22 which engages one end of a compressible spring 24. The other end of the spring 24 engages the trigger flange 8.

A disconnector 26 is disposed adjacent to the connector 12, the disconnector 26 including a forward elongated portion 28 and a rearward elongated portion 30. The rearward elongated portion 30 includes a slot 32 to receive the trigger pin 6, and the terminal 34 of the portion 30 is disposed for engagement with the laterally bent portion 20 of the connector 12. The medial portion of the disconnector 26 includes an elongated slot 36 which receives a hammer pin 38. A hammer 40 is biased by a spring 42 for pivotal movement about the pin 38. The hammer 40 includes a sear-engaging shoulder 44.

A sear 46 is pivotally mounted on the trigger pin 6, the sear 46 including an aperture 52 through which an adjustment screw 54 extends. The screw 54 includes a radially enlarged head 56 having a fluted edge defining alternating ridges 58 and valleys 60. A compressible spring 62 is mounted on the screw 54 to bear against the rearward portion 50 of the sear 46 on one hand, and the screw head 56 on the other hand, when the screw 54 is mounted, the spring 62 serves to bias the sear 46 about the pin 6, as will be explained in more detail hereinafter.

A safety 64 is positioned below the sear 46 and the connector 12 and is operative to lock the trigger mechanism against firing, as will be described in greater detail hereinafter. The safety 64 includes a recess 66 having a cam surface 68 on one side thereof. A detent 70 biased by a spring 72 is disposed below the safety 64 and operates to keep the latter is a preset position, e.g. either on or off.

Referring now to FIG. 2, the trigger mechanism is shown mounted in a trigger housing 74, which in turn is mounted in a firearm receiver 76. A pin 78 and a screw 80 serve to retain the trigger housing 74 in the receiver 76. A bolt assembly 82, including a pair of slide arms 84, is mounted in the receiver, the bolt assembly 82 being shown in FIG. 2 in its battery position. The hammer 40 is shown in its cocked position with the hammer spring 42 serving to bias the hammer 40 in a counterclockwise direction about the pin 38. The lateral portion 48 of the sear 46 engages the hammer shoulder 44 to retain the hammer 40 in its cocked position.

The safety 64 is shown in its off position wherein the con nector projection 16 extends into the safety recess 66. The detent 70 is mounted in a well 86 which also contains the detent spring 72. The detent 70 is urged upwardly into a first concavity 88 is the bottom of the safety 64 to hold the latter in its off position.

The connector lip 14 engages the rear edge of the lateral portion 48 of the sear, the lip 14 being urged into this position by the spring 24. The trigger lug I is in contact with the top edge of the connector 12, the lug being urged into this position also by the spring 24. Thus the spring 24 serves to continuously urge the trigger 2 against the connector 12 so that when the trigger is pulled, the motion imparted to the trigger is immediately transferred to the connector, thereby eliminating preliminary trigger takeup. As previously noted, the spring 24 serves to urge the connector 12 forwardly and downwardly, thus the lateral bend 20 of the connector is urged against the rear terminal 34 of the disconnector 26. The forward elongated portion 28 is thus urged forwardly to a position immediately behind the bolt slide arms 84. It is noted that the elongated slots 32 and 36 in the disconnector 26 permit the latter to slide back and forth over the pins 6 and 38.

The adjustment screw 54 is threaded into the rearward portion of the trigger housing 74, with the spring 62 being sandwiched between the screw head 56 and the rearward portion 50 of the sear 46. It is thus apparent that rotational changes in the position of the screw 54 will vary the quantum of force directed against the sear portion 50 by the spring 62, and thus the trigger pull force necessary to disengage the sear from the hammer 40 can be varied. A rib 90 projects from the rear face of the receiver 76 and engages one of the valleys 60 formed on the screw head 56 when the trigger housing 74 is inserted into the receiver 76. The screw 54 is thus held in place against rotation so as to stabilize the preset trigger pull force. FIG. 3 shows the placement of the rib 90 in one of the valleys 60 and best illustrates how the adjustment screw 54 is locked in place.

FIG. 4 shows the off position of the safety 64, it being noted that, in this position, the connector 12 and the lateral portion 48 of the sear 46 are both disposed over the safety recess 66, thus the connector 12 and sear 46 can both be pivoted downwardly without interference from the safety when the latter is off. It is noted that the detent 70 acts on the first concavity 88 to hold the safety in its off position. The safety 64 also includes a second concavity 92 which cooperates with the detent to hold the safety in its on position, as will be seen more clearly hereinafter.

It is readily apparent from FIGS. 2 and 4, that when the trigger 2 is pulled in a counterclockwise direction, the trigger lug 10 will pivot the connector 12 and the sear 46 in a counterclockwise direction about the pin 6, thus disengaging the sear portion 48 from the hammer 40. The hammer 40 then pivots about the pin 38 and fires the gun. A gas-operated bolt-actuating system (not shown) of conventional design then causes the bolt assembly to reciprocate from its battery position to its retired position and return in a known manner.

FIG. 5 shows the position of the various elements of the trigger assembly when the bolt assembly 82 has moved rearwardly from its battery position during the reciprocation cy cle. As the bolt assembly 82 moves rearward, the slide arm 84 moves against the forward elongated portion 28 of the disconnector 26 and causes the latter to slide rearwardly over the pin 6 and 38. The slide arm 84 overrides the disconnector portion 28 as the latter moves down a camming surface 94 in the receiver 76. Thus the disconnector 26 remains in its rearward position, shown in FIG. 5, during substantially the entire reciprocation cycle of the bolt assembly. As the disconnector 26 is moved to the rear, the rear terminal 34 thereof moves against the laterally bent portion 20 of the connector 12 sliding the latter rearwardly over the pin 6. The connector lip 14 is thus moved out of contact with the sear portion 48 so that the sear 46 is free to pivot independently of the trigger 2 and connector 12. Thus as the hammer 40 is cocked by the rearwardly moving bolt assembly 82, the sear portion 48 is biased upwardly by the spring 62 so that the sear portion 48 will move into engagement with the hammer shoulder 44 when the hammer is cocked. This engagement will occur regardless of the position of the trigger 2 since the latter has been disconnected from the sear. When the bolt assembly 82 has returned to its battery position, the disconnector 26 will be free to slide forward to the position shown in FIG. 2 under the influence of the spring 24 and the connector 12. Thus the spring 24 serves to return the disconnector 26 to its original position, and serves to return the connector 12 into contact with the sear portion 48. When the bolt assembly 82 has returned to its battery position, the gun is again ready to fire.

FIGS. 6 and 7 illustrate the operation of the safety 64. When the safety 64 is pushed to its on position, the connector projection 16 moves up the camming surface 68 onto the exterior surface of the safety. The detent 70 moves into the second concavity 92 to hold the safety in place. When the projection 16 moves onto the exterior surface of the safety 64, the connector 12 is slid rearwardly over the pin 6 and into abutment with the trigger housing 74 at 75, and the connector lip 14 is moved out of engagement with the sear portion 48. Thus the trigger 2 is disconnected from the sear 46 and cannot be used to fire the gun. As a further safety feature, the exterior surface of the safety 64 moves into a position immediately underlying the sear portion 48 so that the latter is locked into engagement with the hammer shoulder 44. Thus the safety renders the trigger inoperable to fire the gun, and also prevents the sear from being accidentally jarred free from the hammer. Since the connector 12 is moved into abutment with the surface 75 on the trigger housing 74 when the safety 64 is on, the trigger 2 cannot be pulled when the safety is on. The immobility of the trigger 2 when the safety 64 is on thus contributes to the feeling of safeness experienced by the shooter.

It is thus readily apparent that the mechanism of this invention operates as a unitary piece when the trigger is pulled to fire the gun, but operates as a plurality of individual units when the bolt assembly is reciprocated. During reciprocation each unit is free to perform its function independently of the other members of the mechanism. The trigger assembly positively precludes firing the gun by pulling the trigger unless the bolt assembly is locked in its battery position. The trigger assembly of this invention also comprises a safety which operates to disconnect the trigger from the sear and to lock the sear into engagement with the hammer, thereby providing dual means for preventing the weapon from being fired when the safety is on.

Since many changes and variations of the disclosed embodiment of the invention may be made without departing from the inventive concept, it is not intended to limit the invention otherwise than as required by the appended claims.

We claim:

I. A mechanism for use with a semiautomatic firearm having a reciprocating bolt assembly, said mechanism comprising:

a. hammer means;

b. sear means operative to engage said hammer means to retain the latter in a cocked position;

c. trigger means; d. connector means disposed in disconnectable engagement with said sear means;

e. spring means connected to said trigger means, said spring means being operative to bias said trigger means against said connector means to provide constant engagement between said trigger means and said connector means, whereby said connector means is operable to immediately transfer motion of said trigger means to said sear means; and

disconnector means operable to contact said connector means and move the latter out of engagement with said sear means when said firearm is fired.

2. The mechanism of claim 1, wherein said spring means is also connected to said connector means to bias the latter into engagement with said sear means and with said disconnector means.

3. The mechanism of claim 1, wherein said disconnector means includes a portion adjacent said bolt assembly to contact said bolt assembly when the latter-is moved out of its battery position, and to thereby move said disconnector means against said connector means.

4. The mechanism of claim I, further comprising adjustable resilient means contacting said sear means to bias the latter toward said hammer means.

5. The mechanism of claim 4, further comprising locking means operative to engage said adjustable means to lock the latter in a preset position.

6. The mechanism of claim 1, further comprising safety means operative to earn said connector means out of engagement with said sear means.

7. The mechanism of claim 6, wherein said safety means is further operative to contact said sear means and lock the latter into engagement with said hammer means.

8. A trigger assembly for use with a semiautomatic firearm having a reciprocating bolt assembly, said trigger comprising:

a. hammer means;

b. a trigger housing on said firearm;

c. trigger means mounted in said trigger housing, said trigger means being connected to said hammer means to retain the latter in a cocked position, and actuation of said trigger means being operative to release said hammer means for movement from its cocked position; and

d. safety means mounted in said trigger housing, said safety means being operable to disconnect said trigger means from said hammer means, thereby rendering said trigger means ineffective to release said hammer means from its cocked position.

9. A trigger assembly for use with a semiautomatic firearm having a reciprocating bolt assembly, said trigger assembly comprising:

a. a trigger housing on said firearm;

b. hammer means movably mounted in said trigger housing;

c. sear means pivotally mounted in said trigger housing, said sear means being movable into engagement with said hammer means to retain the latter in a cocked position;

d. trigger means movably mounted in said trigger housing;

e. connector means slidably mounted in said trigger housing said connector means being slidable into engagement with said sear means;

f. spring means connected to said trigger means, said spring means being operative to bias said trigger means into constant engagement with said connector means, whereby actuation of said trigger means immediately moves said connector means against said sear means to disengage the latter from said hammer means; and

g. disconnector means slidably mounted in said trigger housing, said disconnector being slidable against said connector to slide the latter out of engagement with said sear means thereby freeing said sear means for movement independent of said connector.

10. The trigger assembly of claim 9, wherein said spring means also engages said connector means to urge the latter against said sear means.

ll. A trigger assembly for use with a semiautomatic firearm having a receiver and a reciprocating bolt assembly mounted in the receiver, said trigger assembly comprising:

a. a trigger housing secured to said receiver;

b. hammer means mounted on said trigger housing;

c. sear means mounted on said trigger housing, said sear means being operable to lock said hammer means in a cocked position;

d. spring means contacting said sear means, said spring means being operative to bias said sear means against said hammer means with a predetermined force;

e. adjustment means mounted on said trigger housing and contacting said spring means, said adjustment having a plurality of positions operative to vary the bias of said spring means imposed on said sear means; and

f. means on said receiver operative to engage said adjustment means and lock the latter in a preset position thereby stabilizing said sear bias.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,577 ,827 Dated May 4, 1971 Inventor(s) William J. Billet and Edwin S. Vartanian It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

In Column 1, line 8, the word "more" should be deleted and --move-- should be inserted.

In Column 3, line 6, the word "is" should be deleted and --inshould be inserted.

In Column 3, line 23, the word "is" should be deleted and --inshould be inserted.

Signed and sealed this ll th day of September 1971.

(s EAL) Attest:

,JR. ROBERT GOTTSCHALK Attestlng Officer Acting Commj ssioncr of Patents FORM POJOSO (10'69) USCOMM-DC soars-ps9 h U 5 GOVERNMENT PQINYINU OFFICE I959 0'365381

Claims

1. A mechanism for use with a semiautomatic firearm having a reciprocating bolt assembly, said mechanism comprising: a. hammer means; b. sear means operative to engage said hammer means to retain the latter in a cocked position; c. trigger means; d. connector means disposed in disconnectable engagement with said sear means; e. spring means connected to said trigger means, said spring means being operative to bias said trigger means against said connector means to provide constant engagement between said trigger means and said connector means, whereby said connector means is operable to immediately transfer motion of said trigger means to said sear means; and f. disconnector means operable to contact said connector means and move the latter out of engagement with said sear means when said firearm is fired.

3. The mechanism of claim 1, wherein said disconnector means includes a portion adjacent said bolt assembly to contact said bolt assembly when the latter is moved out of its battery position, and to thereby move said disconnector means against said connector means.

4. The mechanism of claim 1, further comprising adjustable resilient means contacting said sear means to bias the latter toward said hammer means.

6. The mechanism of claim 1, further comprising safety means operative to cam said connector means out of engageMent with said sear means.

8. A trigger assembly for use with a semiautomatic firearm having a reciprocating bolt assembly, said trigger comprising: a. hammer means; b. a trigger housing on said firearm; c. trigger means mounted in said trigger housing, said trigger means being connected to said hammer means to retain the latter in a cocked position, and actuation of said trigger means being operative to release said hammer means for movement from its cocked position; and d. safety means mounted in said trigger housing, said safety means being operable to disconnect said trigger means from said hammer means, thereby rendering said trigger means ineffective to release said hammer means from its cocked position.

9. A trigger assembly for use with a semiautomatic firearm having a reciprocating bolt assembly, said trigger assembly comprising: a. a trigger housing on said firearm; b. hammer means movably mounted in said trigger housing; c. sear means pivotally mounted in said trigger housing, said sear means being movable into engagement with said hammer means to retain the latter in a cocked position; d. trigger means movably mounted in said trigger housing; e. connector means slidably mounted in said trigger housing said connector means being slidable into engagement with said sear means; f. spring means connected to said trigger means, said spring means being operative to bias said trigger means into constant engagement with said connector means, whereby actuation of said trigger means immediately moves said connector means against said sear means to disengage the latter from said hammer means; and g. disconnector means slidably mounted in said trigger housing, said disconnector being slidable against said connector to slide the latter out of engagement with said sear means thereby freeing said sear means for movement independent of said connector.

11. A trigger assembly for use with a semiautomatic firearm having a receiver and a reciprocating bolt assembly mounted in the receiver, said trigger assembly comprising: a. a trigger housing secured to said receiver; b. hammer means mounted on said trigger housing; c. sear means mounted on said trigger housing, said sear means being operable to lock said hammer means in a cocked position; d. spring means contacting said sear means, said spring means being operative to bias said sear means against said hammer means with a predetermined force; e. adjustment means mounted on said trigger housing and contacting said spring means, said adjustment having a plurality of positions operative to vary the bias of said spring means imposed on said sear means; and f. means on said receiver operative to engage said adjustment means and lock the latter in a preset position thereby stabilizing said sear bias.