U.S. patent number 3,863,375 [Application Number 05/378,952] was granted by the patent office on 1975-02-04 for trigger system.
This patent grant is currently assigned to Browning Arms Company. Invention is credited to Bruce W. Browning.
United States Patent |
3,863,375 |
Browning |
February 4, 1975 |
Trigger system
Abstract
A trigger system for a firearm includes a fully adjustable
trigger housing assembly which can be preassembled before insertion
into the firearm receiver. Adjustments for the trigger system
include a trigger tension adjustment, a hammer connector
adjustment, a trigger take-up adjustment, and a trigger backlash
adjustment.
Inventors: |
Browning; Bruce W. (Ogden,
UT) |
Assignee: |
Browning Arms Company (Morgan,
UT)
|
Family
ID: |
23495217 |
Appl.
No.: |
05/378,952 |
Filed: |
July 13, 1973 |
Current U.S.
Class: |
42/69.01;
42/75.03 |
Current CPC
Class: |
F41A
19/16 (20130101) |
Current International
Class: |
F41A
19/00 (20060101); F41A 19/16 (20060101); F41c
019/00 () |
Field of
Search: |
;42/75C,69R,69B,69A,23,24,65,41,42R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Borchelt; Benjamin A.
Assistant Examiner: Jordan; C. T.
Attorney, Agent or Firm: Trask & Britt
Claims
I claim:
1. A trigger system for a firearm comprising:
a trigger housing;
a hammer, pivotally mounted to said housing and carrying catch
means;
a sear, carrying a first lock means for holding the hammer in a
half cock position and a second lock means for holding the hammer
in a fully cocked position, pivotally mounted to said housing to
register respective said lock means with said catch means when said
hammer is pivoted to half cock and full cock positions,
respectively; a trigger pivotally mounted to said housing;
means operably connecting said trigger to said sear to release the
hammer from said fully cocked position upon pulling the
trigger;
nonadjustable bias means mounted to provide a selected minimum bias
of said sear against said hammer; and
second, adjustable bias means mounted for adjustment to
additionally bias said sear against said hammer.
2. A trigger system according to claim 1 wherein said connecting
means includes a connector link pivotally connected to said trigger
and arranged to disengage said sear from said hammer by pulling
said trigger.
3. A trigger system according to claim 2 including means arranged
to bias said connector link toward said sear.
4. A trigger system according to claim 1 further including a pair
of mainsprings and means for seating said mainsprings on said
trigger housing for pivotal motion relative thereto, said
mainsprings being arranged to extend on the sides of the hammer and
connected thereto to drive the hammer upon its release by said
sear.
5. A trigger system for a firearm comprising:
a trigger housing;
a hammer, pivotally mounted to said housing and carrying catch
means;
a sear, carrying a first lock means for holding a hammer in a half
cocked position and a second lock means for holding a hammer in a
fully cocked position, pivotally mounted to said housing to
register respective said lock means with said catch means when said
hammer is pivoted to half cock and full cock positions,
respectively;
a trigger pivotally mounted to said housing;
a connector link pivotally connected to said trigger and arranged
to disengage said sear from said hammer by pulling said
trigger;
means arranged to bias said connector link towards said sear;
and
connector adjustment means which abut said connector link and which
are selectively adjustable to vary the biased position of said
connector link.
6. A trigger system according to claim 5 wherein said connector
link includes a foot positioned above said trigger, and said
connector adjustment means includes an abutment screw threaded
through said trigger to abut against said foot, thereby to adjust
the biased position of said link.
7. A trigger mechanism for a firearm having a receiver and a hammer
comprising:
a trigger housing member with external rails for guiding said
housing into assembled position in the receiver of the firearm;
a trigger, pivotally connected to said housing;
a sear which is pivotally connected to said housing and which has a
first lock means for holding the firearm hammer in a half cock
position and a second lock means for holding the hammer in a full
cock position;
means operably connected between said trigger and said sear in said
housing for releasing said sear from said hammer in full cock
position upon actuation of said trigger;
said trigger housing being insertable in said firearm with said
sear, said hammer, and said connecting means all preassembled
therein;
nonadjustable bias means mounted to provide a selected minimum bias
of said sear against said hammer; and
second, adjustable bias means mounted for adjustment to
additionally bias said sear against said hammer.
8. A trigger system according to claim 7 further including a pair
of mainsprings and means for seating said mainsprings on said
trigger housing for pivotal motion relative thereto, said
mainsprings being arranged to extend on the sides of the hammer and
connected thereto to drive the hammer upon its release by said
sear.
9. In a firearm including a trigger housing mounted within a
receiver thereof and a sear, trigger, linking means, and mainspring
all mounted in operable arrangement within said trigger housing to
operate and control the cocking and firing action of a hammer, the
improvement which comprises:
pivotally mounting said sear, trigger, and linking means within
said trigger housing;
substantially vertical rails on the outer walls of said housing
tapering to a narrower width at the top;
pin means transversely mounted in said trigger housing with its
respective ends terminating approximately flush with the outside
edges of said vertical rails and projecting rearward from said
rails;
corresponding vertical slots within the receiver arranged to
receive said vertical rails and including recesses arranged to
receive the end portions of said pin means when said trigger
housing is installed in said receiver;
means adapted to bear against one end of said mainspring and
transmit the force thereof to said trigger housing thereby
temporarily to hold said trigger housing in place; and
means for permanently securing said housing in said receiver.
Description
BACKGROUND OF THE INVENTION
1. Field:
The present invention relates to a trigger system for firearms and,
more particularly, to a trigger system for rifles or handguns.
2. State of the Art:
The "feel" of a firearm, especially that of a rifle, is quite
important to the enthusiast because each person handles a firearm
in his own manner. Consequently, it is commercially desirable that
a manufacturer incorporate adjustment means into the firearm,
particularly into the trigger. In many firearms, the trigger
tension adjustment is directly related to the amount the trigger
must move before the hammer is released. In such firearms, a fine
trigger is often referred to as a "hairtrigger" , meaning that it
need move only slightly to cause the weapon to fire. Hairtriggers
are generally regarded as undesirable and unsafe. On the other
hand, trigger systems having a number of adjustments incorportated
thereinto have heretofore required a rather complex and prolonged
assembly operation.
Accordingly, an object of the present invention is to provide a
fully adjustable trigger system yet one which is readily and
quickly assembled or taken down.
SUMMARY OF THE INVENTION
The trigger system of the invention includes a sear having a first
notch for holding the firearm's hammer in a half cock position and
second notch for holding the hammer in a fully cocked position. The
system may include a first, nonadjustable biasing means which
provides a minimum safe bias on the sear to hold it against the
hammer, and a second, adjustable, biasing means for adjustably
biasing the sear against the hammer. The means connecting the
firearm's trigger to the sear may include a connector link which is
arranged to disengage the sear from the hammer in response to
pulling on the trigger. The trigger spring is arranged to bias the
connector toward the sear, and an adjustment may be included to
vary the biased position or direction of the connector.
The trigger system, as described hereinafter, can be assembled to a
trigger housing so that it may be slipped, fully assembled, into
the firearm's receiver. A pair of mainsprings can be used, and the
trigger housing is configurated to provide clearance for associated
mainspring guides, mainsprings and pins.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention may be further understood by referring to the
following description and appended drawings, which are offered by
way of example only and not in limitation of the invention, whose
scope is defined by the appended claims and equivalents.
In the drawings:
FIG. 1 is an exploded pictorial view showing a trigger mechanism
according to the invention;
FIG. 2 is a cross sectional view of the mechanism of FIG. 1 in
assembled condition, the cross section being taken in a vertical
plane through the axis of the mechanism of FIG. 1;
FIG. 3 is a cross sectional view taken in the same plane as FIG. 2,
but showing the mechanism in another position;
FIG. 4 is a cross sectional view taken in the same plane as FIG. 2,
but showing the mechanism in still another position;
FIG. 5 is a side elevation of the trigger housing illustrated in
FIG. 1 with the associated mainsprings in their operative position;
and
FIG. 6 is a sectional detail through one side of the trigger
housing illustrated in FIG. 1.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT
The trigger mechanism of FIG. 1 is shown in conjunction with a
rifle having a butt stock 9, a hammer 10, and a breech block 11.
Since the present invention concerns essentially only the trigger
mechanism, the remainder of the rifle is not shown and may be
regarded as conventional. Although a rifle is suggested by the
drawings, the inventive mechanism may obviously be utilized with
other types of firearms.
The trigger mechanism includes a trigger housing generally
designated 13 in FIG. 1 which is fitted into a receiver 14 (see
FIGS. 2 - 4) which is, in turn, connected at one end to the butt
stock 9 and at the other end to a barrel (not shown). Although the
receiver is not fully illustrated, it may be regarded as a
conventional housing for the trigger mechanism, the hammer and
other components. For present purposes, the receiver may be
understood to include the recess 12 formed in the forward end of
the butt stock 9 which surrounds and supports the trigger housing
as will be hereinafter described. Commonly assigned, copending U.S.
Pat. application Ser. No. 360,619, filed May 16, 1973, now U.S.
Pat. No. 3,830,000 the disclosure of which is incorporated by
reference, describes a receiver which is particularly adapted for
use with the mechanism described hereinafter.
The trigger housing 13 illustrated is a one-piece member which has
a bifurcated front wall comprising the two pairs of ears 15a and
15b, and 16a and 16b, respectively, which extend forward in
spaced-apart relationship, one pair above the other. The vertical
slot 17 defined between the ears 15, 16 serves as a guide for a
connector 18, as will be described in detail hereinafter. The
V-shaped notches 19 on either side of the trigger housing between
the corresponding ears of the respective pairs serve to seat the
mainspring spacer 20 (a short tubular member), as will also be
described in detail hereinafter. The trigger housing is held
stationary in the butt stock recess 12 by a bolt 21 (see FIGS. 2
and 3) which extends through the butt stock and threads into the
rear of the trigger housing.
As shown, and inverted, L-shaped trigger 22 is pivotally held in
the trigger housing between the lower set of ears 16a and 16b by
pivot pin 23 so that it pivots at its vertex. The foot 22a of the
trigger extends rearward and thus moves in a vertical arc within
the trigger housing when the trigger is pulled or released. The
upper surface of the trigger foot 22a is shown with a horizontally
extending slot 24 formed therein, into which is pivotally connected
the aforementioned connector 18. The connector 18 extends up
through the aforementioned vertical slot 17 in the trigger housing
between the housing ears 15, 16. The lower, pivoted end of the
connector 18 is formed as a foot 26 which extends forward from the
connector pivot pin 27. The pin 27 is retained within the trigger
22 by the adjacent ears 16a and 16b.
In the illustrated arrangement, a spiral-wound trigger spring 29 is
slidably disposed over the trigger pin 23. The opposed ends 30a and
30b of the trigger spring extend in the same direction and are
placed so that they ordinarily bias the trigger forward. (In other
words, the spring 29 urges the trigger 22 to rotate clockwise in
the drawings.) More particularly, the end 30b of the spring 29
presses against the top of the trigger. The connector is urged to
pivot counterclockwise by a connector spirng 31 until its foot 26
abuts the end of an adjustment screw 32 (called the connector
screw) which extends up through the trigger 22. The connector screw
32 acts as a forward stop to the connector 18 and may be adjusted
to allow the connector to contact a sear (43 described hereinafter)
in the proper manner.
The trigger 22 is selectively stopped from pivoting forward or
clockwise by a "trigger take-up" 34 which is threaded into the
bottom of the trigger housing 13. In the illustrated arrangement
(see FIGS. 2 and 3), a lip 36 on the end of the trigger foot 22a
catches the head 37 of the take-up screw 34, thereby being stopped
from pivoting further. The lip 36 is at the top of a slot formed in
the rear face of the trigger foot, and is thus hidden in FIG. 1.
The distance which the take-up screw 34 is threaded into the
trigger housing governs the forward stop position of the
trigger.
The travel of the trigger in the rearward, or counterclockwise,
direction is determined by a "backlash" adjusting screw 38 which is
threaded through the foot 22a of the trigger 22. The trigger can be
pulled back until the tip of the backlash screw 38 abuts the
surface 13a of the trigger housing 13. The further the backlash
screw is threaded through the trigger foot, the less the distance
the trigger can pivot back. In practice, the backlash screw is
desirably adjusted to stop the rearward movement of the trigger
just after the trigger has released the hammer from the full cock
position.
The hammer catch mechanism includes a V-shaped sear, generally
designated 43, which is rotatably mounted between the upper pair of
trigger housing ears 15a and 15b by pivot pin 44. The sear is
positioned so that one of its legs 43a extends back over the
trigger housing adjacent the upper end of the connector link 18 and
its other leg 43b extends downward into the receiver adjacent the
rear of the hammer 10. The end of the rearwardly extending leg 43a
of the sear has a horizontally extending groove 47 formed therein.
A pin 45 (called the sear spring rest pin) extends through the sear
in front of and parallel the groove 47. The ends of the sear spring
rest pin 45 extend slightly to either side of the sear. (The sides
of the sear are hereinafter referred to as the left and right
sides, the left side being the one which can be seen in the
drawings.) Across the end of the sear spring rest pin 45 which
extends from the right side of the sear is placed the extended end
wire 51a of a spiral-wound spring 51 (called the sear spring). The
spring 51 is mounted about a pin 52 (called the sear spring pin)
fitted through the side walls 53a and 53b of the housing 13. The
side walls 53a and 53b define a groove 54 across the top of the
trigger housing 13 which retains the other end wire 51b of the sear
spring 51. Accordingly, the sear spring 51 urges the sear 43 to
rotate in the clockwise direction.
As best illustrated by FIGS. 1 and 6, ends of rest pin 45 are
received by relief cuts 45a in the side walls 53a and 53b of the
trigger housing 13. A trigger pull adjustment member 55 is mounted
to pivot on pin 52 with one end 55a of the member atop the rest pin
45. As shown, the bias of the member 55 is adjustable whereas that
of the sear spring is not.
Refereing to FIG. 6, a vertical bore 56 is formed through the
trigger housing side wall, and a cylindrical spring guide member 57
is slidably installed therein. A spring 58 is installed in the bore
56 between the spring guide 57 and the end 55b of the trigger pull
adjustment member 55. A portion 57a of the spring guide 57 is of
reduced diameter to fit within the coils of the spring 58. The bias
applied by the member 55 to the sear end 43a is adjusted by turning
screw 59 to raise the spring guide 57 in the bore 56. In effect,
the member 55 duplicates the function of the sear spring 51, but it
is the sear spring 51 which provides a minimum bias to the sear,
thereby effectively inhibiting "hairtrigger" adjustments.
Without the biasing force of the sear spring 51, the sear 43 should
rotate freely. Its clockwise rotation is stopped when its
rearwardly directed leg 43a strikes a pin 61 (called the "trigger
housing pin") which is secured traversely across the bifurcated
front wall of the trigger housing 13. Ordinarily, the downwardly
extending leg 43b of the sear 43 is biased against the back of the
hammer 10 by the springs 51 and 58.
The trigger mechanism described (i.e., the trigger housing,
together with the parts pivotally connected thereto) can be
assembled apart from the firearm. The trigger mechanism is then
slipped, fully assembled, into the receiver and held in place by
the mainspring pin 63b urged back into the V-slot 19 by the
mainsprings 71a and 71b, as shown in FIG. 5. Guide rails 64 formed
integral with the trigger housing sidewalls ride in corresponding
slots 65 in the receiver sides to properly position the trigger
mechanism therein. For ease of assembly, the rails 64 are desirably
tapered downward from a narrow upper end, as shown. The pin 61 is
inserted into the trigger housing until its ends are flush with the
outside surfaces of the rails 64. The combined width of the pin 61
and rails 64 is slightly less than the width of the slots 65. A
recess 65a is provided in each slot 65, and the trigger housing is
inserted until the ends of pin 61 align with these recesses 65a.
The housing 13 then moves slightly rearward to seat the pin 61. The
entire mechanism is held temporarily in position by the force
transferred by the mainsprings 71a and 71b to the trigger housing
13. Once in position in the receiver, the butt stock bolt 21 can be
threaded into the rear of the trigger housing to hold it securely
in place.
The structure and function of the trigger and mainsprings are best
understood by considering FIGS. 2 - 4 which consecutively show the
uncocked, fully cocked, and haf cocked positions of the hammer. In
the illustrated arrangememt, the forward face of the downwardly
extending leg of the trigger sear 43 is tapered slightly
off-vertical and has a notch 66 formed therein. The taper of the
sear generally is tangent to the configuration of the back of the
hammer, which is convex when viewed from the side. The hammer is
pivoted at pivot pin 68 and the curvature of the back of the hammer
is not quite circular with respect to the hammer pivot point.
Accordingly, the sear 43, which is biased to pivot clockwise
against the back of the hammer 10 by the sear spring 51, pivots
with the hammer. The hammer can be cocked manually or it may be
forced back, for example, by the pressure of the breech block 11
against the hammer roller 72 when the breech block is moved; e.g.,
by a lever-action mechanism of the type described in the aforesaid
copending patent application Ser. No. 360,619 now U.S. Pat. No.
3,830.000.
The two mainsprings 71a and 71b, respectively, are the illustrated
means which drive the hammer forward (i.e., the mainsprings pivot
the hammer in counterclockwise direction). The mainsprings shown
are spiral compression springs which are slidably fitted about an
associated pair of guide rods 73a and 73b. The guide rods are
mounted to pivot and to telescope, within limits, in the mainspring
pivot pins 63, which are in turn rotatably mounted at the opposite
ends of the guide rods. The pin 63a at the forward ends of the rods
is mounted in a channel 74 (FIG. 1) formed through the hammer, and
extends from both sides of the hammer. The pin ends are apertured
75a to slidably receive the forward ends of the guide rods 73and
73b so that in assembled condition, the mainsprings 71a and 71b are
held on opposite sides of the hammer 10.
In the illustrated embodiment (see particularly FIGS. 1 and 5) the
forward ends of the mainspring guide rods 73a and 73b have collars
76 formed thereon against which the mainsprings 71a and 71b press.
The collars stop the guide rods from slipping forward; the rear
ends of the guide rods have no collar, and can thus telescope back
through apertures 75b in the mainspring pin 63b which is seated
against the trigger housing 13. The guide rods 73a and 73b extend
back on either side of the connector 18 through grooves 77 formed
at the back of the V-shaped notches 19. With the mainsprings under
compression, the guide rods 73a and 73b extend into circular
recesses 78 formed in the sides of the trigger housing 13. The
mainsprings and associated guide rods are thus provided with ample
space within which to function.
The functioning of the mainsprings is relatively uncomplicated. As
the hammer 10 falls, the pins 63 turn slightly and the rearward
ends of the guide rods 73a and 73b withdraw slightly from the
associated apertures 75b in the pin 63b at the trigger housing 13.
Concomitantly, the mainsprings 71a and 71b extend in length. When
the hammer is cocked back, the opposite occurs; the guide rods 73a
and 73b slide into the apertures 75b in the back pin 63b, and the
mainsprings 71a and 71b are put into compression. FIG. 5 shows one
of the mainsprings 71a pivoted and compressed in phantom lines.
The hammer 10, as illustrated in FIGS. 3 and 4, has two catch
("cocked") positions. The positions are respectively called the
full cock and half cock positions. The half cock position (FIG. 4)
occurs when the notch 81 (catch means) on the hammer catches in the
first notch 66 in the sear 43. When the hammer is in the half cock
position, the gun is on "safe" , and the trigger will not release
the hammer (because the upper end of the connector 18 is not under
the lip 46 on the rearwardly extending leg of the sear). The half
cock sear notch 66 also functions as a safety mechanism during
manual cocking of the hammer, in that if the thumb should slip
during manual cocking, the sear notch 66 will catch the hammer at
the half cock position. If the trigger is pulled, the notch 66 is
pivoted out of registering position with the hammer notch 81 to
permit the hammer 10 to fall.
In the full cock position (FIG. 3), the gun is ready to be fired.
The full cock position occurs when the hammer is forced completely
back, thereby pivoting the sear 43 counterclockwise until the sharp
lower end 82 of the sear catches in the hammer notch 81 as shown.
When the sear 43 pivots counterclockwise, it also pushes the
connector 18 back slightly to an energized position against the
trigger spring 29. Accordingly, the connector is automatically
urged to pivot under the sear lip 46 when the sear end is pivoted
(i.e., raised) sufficiently by the urging of the hammer. The
trugger take-up screw 34 should be adjusted so that the trigger
need not move back excessively before the connector contacts the
sear; if the trigger were set too far forward, the connector 18
would not pivot forward (counterclockwise) and catch under the sear
lip 46 when the full cock position was reached. The trigger take-up
screw 34 should also position the trigger far enough forward to
allow the connector to disconnect from the sear in the half cock
position; otherwise, the connector could never release the sear,
and the sear could never move into half cock position.
Pulling the trigger 22 releases the hammer 10 from full cock. As
the trigger foot 22a rises, so does the connector 18 which, in
turn, pivots the sear 43. The sear pivots until it is no longer
caught in the hammer notch 81; and then the mainsprings 71a and 71b
drive the hammer forward to strike the rear of the breech block 11
to impart firing energy to the firing pin 83 (FIG. 1).
* * * * *