U.S. patent number 3,631,620 [Application Number 04/836,448] was granted by the patent office on 1972-01-04 for bolt of bolt-action firearms.
This patent grant is currently assigned to Howa Kogyo Kabushiki Kaisha. Invention is credited to Banri Ohira.
United States Patent |
3,631,620 |
Ohira |
January 4, 1972 |
BOLT OF BOLT-ACTION FIREARMS
Abstract
A firearm bolt assembly including a firing pin with an
engagement part which is aligned with and permitted to enter an
engagement slot in a bolt cylinder into a position whereby firing
is possible only when the bolt cylinder is in its fully locked
position. The driving force of the main spring initially borne by
the engagement part in contact against a shoulder part of the
cylinder is transferred, when the engagement part thus enters the
slot, to the catch of the cooking piece thereby brought into
contact with and arrested by the sear in preparation for
firing.
Inventors: |
Ohira; Banri (Aichi-ken,
JA) |
Assignee: |
Howa Kogyo Kabushiki Kaisha
(Aichi-ken, JA)
|
Family
ID: |
12702628 |
Appl.
No.: |
04/836,448 |
Filed: |
June 25, 1969 |
Foreign Application Priority Data
|
|
|
|
|
Jun 29, 1968 [JA] |
|
|
43/44839 |
|
Current U.S.
Class: |
42/16;
42/69.02 |
Current CPC
Class: |
F41A
3/22 (20130101); F41A 19/34 (20130101) |
Current International
Class: |
F41A
19/34 (20060101); F41A 19/00 (20060101); F41A
3/22 (20060101); F41A 3/00 (20060101); F41c
011/00 (); F41c 017/06 () |
Field of
Search: |
;42/16,16.1,69A,70 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Borchelt; Benjamin A.
Assistant Examiner: Jordan; C. T.
Claims
I claim:
1. In a bolt device of a bolt-action firearm having a receiver, and
a sear, and adapted for sliding and rotating bolt action within
said receiver and of the type comprising a firing pin having an
engagement part; a bolt body having a hollow interior for
accommodating said firing pin; an engagement slot in the bolt body
permitting passage therethrough in an axial direction of said
engagement part only when said part is angularly aligned with said
slot thereby to permit the firing pin to be impelled forward in
firing motion, said bolt body being rotatable, when in the
longitudinally closed state, between an angular unlocked position
and an angular fully locked position; a main spring imparting an
elastic forward force to said firing pin; and a cocking piece
adapted for cooperative operation with a cam recess in the bolt
body and having a catch part for engagement with said sear, the
engagement part being out of alignment with the engagement slot
when the bolt body is not in said fully locked position and being
permitted to slide into the engagement slot only when the bolt body
is in the fully locked position, thereby to enable the firing pin
to be impelled forward in firing motion, the improvement wherein
said cocking piece is connected to said firing pin in a manner such
that, while said engagement part of the firing pin is not aligned
with the engagement slot and is prevented from advancing forward,
the cocking piece is disposed in a position spaced apart from said
sear.
2. The bolt device as claimed in claim 1 wherein said main spring
is a coil spring connected at one end thereof to said engagement
part and at the other end thereof to a bolt sleeve which does not
rotate relative to the receiver, whereby resistance to unlocking is
imparted to said bolt body when the bolt body is rotated from the
locked position toward the unlocked position thereof.
3. The bolt device as claimed in claim 1 wherein said engagement
slot has shoulder parts at a rear entrance thereof and said
engagement part has a front extremity for abutting against said
shoulder parts when the engagement part and slot are not in
alignment, corner parts of said front extremity and said shoulder
parts being rounded to impart a cam action thereto whereby a torque
urging said bolt body to rotate automatically into said fully
locked position is imparted thereto from an angular position
thereof slightly before the fully locked position.
4. The bolt device as claimed in claim 1 wherein said cocking piece
is fitted slidably onto a rear end of said firing pin and prevented
from being disconnected therefrom by a stop device.
5. The bolt device as claimed in claim 2 wherein said firing pin is
rotatable about the axis thereof with respect to said cocking piece
within a rotational angle range determined by a limiting device,
and said main spring imparts a torque to the firing pin
6. The bolt device as claimed in claim 4 wherein said stop device
comprises a pin passing through said firing pin transversely
thereto.
7. The bolt device as claimed in claim 4 wherein said stop device
comprises a pin pivotally secured in a split groove at the rear end
of said firing pin.
8. The bolt device as claimed in claim 4 wherein said stop device
comprises a pin pivoted within a split groove at the rear end of
said firing pin for freely emerging from and retracting into said
groove and continually urged outward by a spring.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to firearms and firing mechanisms
thereof and more particularly to a new and improved bolt mechanism
which can be advantageously applied to almost all kinds of
bolt-action firearms including rifles and shotguns.
A representative bolt-locking mechanism in bolt-action rifles of
types commonly known heretofore has a bolt housing and guiding
frame or receiver provided on its inner wall surface with a lug for
locking and a bolt cylinder or bolt body adapted to be inserted
longitudinally into the receiver in the longitudinal direction
thereof and having a lug for locking on the periphery of the front
extremity thereof.
This bolt body is further adapted to be supported rotatably about
its axis within the receiver between an unlocked position in which
the locking lug thereof does not engage the locking lug of the
receiver, and also the bolt body can retract rearwardly within the
receiver and a locked position in which the locking lug of the bolt
body engages with the locking lug of the receiver, and the rearward
retraction of the bolt body is arrested. Furthermore, the bolt body
contains therein a firing pin about which a main spring is wound.
This firing pin is impelled by the main spring in the compressed
state to plunge forward and thereby to accomplish firing upon
release of the cocking piece by the sear, which is caused by the
manipulation of the trigger to protrude into and retract from the
receiver interior.
In known rifles having bolts of this character, there have been
instances wherein, even when the bolt handle of the bolt body is
partially rotated in the direction for locking, and a cam groove
formed on the rear end surface of the bolt body has merely reached
a position at which it is partially confronting the cocking piece,
whereby the bolt is not fully locked, the cocked firing pin is
released when the trigger is pulled because of carelessness or some
kind of impact force. Consequently, the cocking piece is released
and moves forward, sliding along the inclined surface of the cam
groove, whereby the firing pin is impelled forward to cause
accidental firing.
At the time when an accidental firing of this nature occurs, the
locking lug of the bolt body and the locking surface of the locking
lug of the receiver have not yet fully engaged. If the area of
pressure contact between the two locking lugs is thereby very
small, the bolt will be incapable of resisting the force due to the
gas pressure of the firing in the firing chamber, and a part of the
locking lug of the bolt body or the locking lug of the receiver
will be sheared off, whereby the bolt body will be impelled
violently toward the rear. As a result of such accidental firing,
there have been instances of injury to the person handling the gun
and of damage to the receiver and/or bolt.
While such accidents relating to firearm mechanisms are very rare,
they cannot be neglected or permitted since they are a source of
danger to persons handling the firearms.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a bolt device
of a bolt-action firearm capable of positively preventing accidents
of the above-described nature.
Another object of the invention is to provide a bolt device of the
above-stated character in which the bolt body is automatically
compelled to rotate toward the lock position thereof from a
position immediately therebefore, whereby the rotation of the bolt
toward and into the fully locked position is facilitated.
Still another object of the invention is to provide a bolt device
of the above-stated character in which the torque resistance to
rotation of the bolt body from the locked position toward the
unlock position is relatively high.
A further object of the invention is to provide a bolt device of
the above-stated character in which, when the bolt is not in its
fully locked state, the cocking piece and the sear for releasing
the cocking piece are maintained in a mutually spaced-apart state
and cannot contact each other, the cocking piece and the sear
engage only when the bolt is in its fully locked state to make
firing possible.
A still further object of the invention is to provide a bolt device
of the above-stated character in which the firing pin is inserted
through the cocking piece in a relatively rotatable and, moreover,
a freely detachable manner with respect thereto, and, at the same
time, the range of rotational angle of the firing pin relative to
the cocking piece is limited, whereby the firing pin is caused to
have a specific rotational range, and, moreover, the disassembly
and assembly of the bolt is facilitated.
Other objects and advantageous features of the present invention
will presently become apparent as the disclosure proceeds.
According to the present invention, briefly summarized, there is
provided a bolt device of the character referred to above in which
the firing pin has an engagement part having a distinctive cross
section which is aligned with and permitted to enter a
corresponding engagement slot in the bolt cylinder or body in the
forward direction into a position whereby firing is possible only
when the bolt body is in its fully locked position, the forward
driving force of the main spring being initially borne by the
engagement part in contact against a shoulder part of the bolt body
but being transferred to the catch of the cocking piece brought
into contact with and arrested by the sear in preparation for
firing when the engagement part thus enters the engagement
slot.
The nature, principle, details, and utility of the invention will
be more clearly apparent from the following detailed description
with respect to preferred embodiments of the invention when read in
conjunction with the accompanying drawings, in which like parts are
designated by like reference numerals.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a side (right-hand) elevation, with parts cut away,
showing the essential parts of an example of a bolt device
according to the invention with the bolt in its unlocked state;
FIG. 2 is a similar side elevation showing the bolt illustrated in
FIG. 1 in its fully locked state prior to firing;
FIG. 3 is a similar side elevation showing the same bolt in its
firing state with the firing pin in the released and advanced
state;
FIG. 4 is a right-hand side elevation of the firing pin assembly
extracted from the bolt device shown in FIG. 1;
FIG. 5 is a right-hand side elevation showing a cocking piece
included in the firing pin assembly illustrated in FIG. 4;
FIG. 6 is a right-hand side elevation showing a bolt sleeve
included in the same firing pin assembly;
FIG. 7 is a right-hand side elevation showing the bolt cylinder or
body of the bolt device illustrated in FIG. 1;
FIG. 8 is an end elevation of the firing pin assembly illustrated
in FIG. 4 as viewed from the right therein (rifle muzzle side);
FIG. 9 is an end elevation of the firing pin assembly illustrated
in FIG. 4 as viewed from the left therein (rifle butt side);
FIG. 10 is an end elevation of the bolt device shown in FIG. 1 as
viewed from the right therein (rifle muzzle side);
FIG. 11 is a fragmentary section taken along the central vertical
plane indicated by line XI--XI in FIG. 9 as viewed in the arrow
direction;
FIG. 12 is a fragmentary section taken along the central horizontal
plane indicated by line XII--XII in FIG. 10 as viewed in the arrow
direction;
FIG. 13 is an end elevation of the bolt device illustrated in FIG.
2 as viewed from the right therein (rifle muzzle side);
FIG. 14 is a fragmentary section taken along the central horizontal
plane indicated by line XIV--XIV in FIG. 13 as viewed in the arrow
direction;
FIG. 15 is an end elevation of the bolt body illustrated in FIG. 7,
as viewed from the left therein (rifle butt side), showing the
interior in an insertion hole of the bolt body with the firing pin
extracted;
FIGS. 16, 17, and 18 are fragmentary diagrammatic views indicating
the relationships between the cocking piece and a cam slot
respectively in the states indicated in FIGS. 1, 2, and 3;
FIG. 19 is a fragmentary side elevation showing a modified example
of coupling means of the cocking piece and the firing pin;
FIG. 20 is an end elevation of the parts illustrated in FIG. 19 as
viewed from the left therein, (rifle butt side);
FIG. 21 is a fragmentary side elevation showing another modified
example of the coupling means of the cocking piece and the firing
pin;
FIG. 22 is an end elevation of the parts shown in FIG. 21 as viewed
from the left therein;
FIG. 23 is a view similar to FIG. 19 showing still another
modification of the coupling means of the cocking piece and the
firing pin;
FIG. 24 is an end elevation of the parts illustrated in FIG. 23 as
viewed from the left thereof.
FIG. 25 is a view similar to FIG. 19 and is a section taken along
the central vertical plane indicated by line XXV--XXV in FIG. 26 as
viewed in the arrow direction, showing a further modification of
the coupling means of the cocking piece and the firing pin; and
FIG. 26 is a cross section taken along the vertical plane indicated
by line XXVI--XXVI in FIG. 25 as viewed in the arrow direction.
DETAILED DESCRIPTION
Referring first to FIGS. 1, 2, and 3, the firearm (rifle) bolt
designated generally therein by reference numeral 1 consists,
essentially, of a bolt cylinder or body 3 as shown in FIG. 7 and a
firing pin assembly 2 as shown in FIG. 4 fitted slidably within the
bolt body.
As shown most clearly in FIGS. 4, 5, and 6, the firing pin assembly
2 comprises a firing pin 4, a bolt sleeve 5, a cocking piece 6, and
a firing pin spring or main spring 7. As shown in FIG. 4, the
firing pin 4 has a stop flange 8 of disk shape near its front end
(right end as viewed in FIG. 4) and an engagement part 9 which is
integrally and contiguously formed with the flange 8 and extends
forwardly therefrom. This engagement part 9 has a substantially
oblong cross section and, furthermore, two edges of relatively long
dimensions between opposed sides, and muzzle side surfaces thereof
are chamfered into arcuate shoulders 9a, 9a.
A bolt sleeve 5 is fitted onto the base or rear end (left end as
viewed in FIG. 4) of the firing pin 4, and a main spring 7 is
installed between this bolt sleeve 5 and the aforementioned stop
flange 8 and around the middle shank part of the firing pin 4. The
bolt sleeve 5 is made up of a large diameter cylindrical part 5a
and a small diameter cylindrical part 5b as shown in FIGS. 4 and 6
and is provided internally therethrough in the axial direction with
a large diameter bore 10 and a small diameter bore 11 contiguous
thereto. A slot 12 is formed in the large diameter cylindrical part
5a in the axial direction thereof.
A cocking piece 6 if further fitted onto the base end (left end) of
the firing pin 4 and, as shown in FIG. 5, is made up of a
cylindrical part 6a and a cocking catch part 6b of plate form. The
cylindrical part 6a is provided axially through its interior with a
large diameter bore 14 and a small diameter bore 15.
The rear or base end part of the firing pin 4 is inserted rearward
through the bores 15 and 14 and projects outward toward the rear,
being held by a stop pin 16 passed therethrough. The main spring 7
is thereby compressed between the stop flange 8 and the bolt sleeve
5a. In the installation of this main spring 7, the two ends thereof
are respectively engaged with and anchored in cutouts 18 and 19
formed respectively in the stop flange 8 and bolt sleeve 5a.
Moreover, a residual torsional force or torque should be forcibly
imparted previously to the main spring 7 itself.
When the cocking piece 6 is assembled in the state indicated in
FIG. 4, the catch part 6b thereof is inserted slidably into the
slot 12 of the bolt sleeve 5a, and the cylindrical part 6a thereof
is inserted slidably into the large bore 10 of the bolt sleeve
5a.
The above-mentioned stop pin 16 is adapted to contact a rotational
stop 21, which projects into the large diameter bore 14 at the base
end or rear end of the cocking piece 6 as shown in FIGS. 9 and 11,
thereby to establish one limit to the rotational angle range of the
firing pin 4 under the torque due to the main spring 7.
Accordingly, the engagement part 9 near the front end of the firing
pin is held in the horizontal position as indicated in FIG. 4.
As shown in FIG. 7, the bolt body 3 has therewithin in the
longitudinal direction a chamber or bore 23 for insertion therein
of the firing pin, which bore 23 has an inner diameter such that
the small diameter cylindrical part 5b of the bolt sleeve 5 can be
inserted therein with a sliding fit. The bolt body 3 is provided at
its rear end with a bolt handle 24 integrally formed therewith. In
the example illustrated, the bolt rotational angle is 90.degree.
and the bolt handle 24 extends outward in a substantially straight
line perpendicular to the bolt axis.
The bolt body 3 is provided in its interior contiguously forward of
the bore 23 with an engagement slot 25 of an oblong cross section,
the axis of its longer dimension being vertical when the bolt is in
the angular position indicated in FIGS. 1, 7, and 15. This
engagement slot 25 is open to the outside at the upper surface (the
bolt handle side) of the bolt body 3 as shown particularly in FIGS.
2 and 3. The width of the slot as measured perpendicularly to its
longitudical direction is made slightly larger than the narrower
dimension in cross section of the engagement part 9 of the firing
pin 4.
At the juncture of the bore 23 for insertion of the firing pin and
the engagement slot 25, ledges or shoulders 26 of arcuate shape are
formed. Contiguous to and forward of the engagement slot 25 there
is formed a through hole 27 of small diameter in the forward part
of the bolt body 3. The diameter of this hole is made slightly
larger than the outer diameter of the forward end part 4a (FIG. 4)
of the firing pin assembly 2.
The bolt body 3 is further provided on opposite lateral sides of
its front end part with a pair of locking lugs 28 projecting
outwardly. The bolt body 3 also has a cam recess 29 at the lateral
side of its base or rear end part.
The firing pin assembly 2 and the bolt body 3 are assembled in the
state indicated in FIG. 1. More specifically, the firing pin 4 is
inserted into the firing pin insertion bore 23 within the bolt body
3, and the arcuate shoulder parts 9a, 9a (FIG. 4) forming the
forward extremity of the engagement part 9 of oblong cross section
of the firing pin 4 are caused to engage with the above-mentioned
shoulder parts 26 of the bolt body 3. Since the orientation about
the longitudinal axis of the engagement slot 25 and that of the
engagement part 9 are not coincident in this assembly state, i.e.,
substantially at right angles, the engagement part 9 cannot advance
further forward.
The above described engagement mechanism including the shoulder
parts 9a and the shoulder parts 26 constitutes one of the important
technical features of the present invention.
After the engagement part 9 has been placed in abutting engagement
with the shoulder part 26, the bolt sleeve 5 is forced forward to
cause the small diameter cylindrical part 5b thereof to slide over
and along the firing pin 4 as the main spring is compressed,
thereby to be forced into the interior of the bore 23 for insertion
of the firing pin. In this assembly step, the cylindrical part 5b
of the bolt sleeve 5 is pushed forward with a lug 30 (as shown in
FIGS. 4 and 6) provided on the peripheral surface thereof in a
state of insertion in a groove 23a (FIG. 7) formed in the axial
direction at the rear end of the bore 23 in the bolt body. Then,
when the bolt sleeve 5 has been advanced forward to a point where
the lug 30 reaches an annular groove 23b in the bore 23, the bolt
sleeve 5 is rotated.
The lug 30, groove 23a, and annular groove 23b thus constitute a
so-called bayonet lock device whereby the front end surface of the
large diameter cylindrical part 5a of the bolt sleeve 5 abuts and
contacts the rear end surface of the bolt body 3 as indicated in
FIG. 1.
After the firing pin assembly 2 has been fitted in the bolt body 3
as described above, the resulting assembly is inserted into the
frame or receiver 32 of the rifle as indicated in FIG. 1.
The inner surface of the axial bore 33 within the receiver 32 is
provided with a diametrically opposed pair of upper and lower
arcuate lugs 34 for locking, between which are provided a pair of
cutout parts each of a transverse dimension such as to permit
passage therethrough in the axial direction of the locking lugs 28,
28 of the bolt body 3. Therefore when the angular positions of the
locking lugs 28 are caused to coincide with those of the cutout
parts, and the bolt body is then pushed forward, the lugs 28 reach
the position indicated in FIG. 1 in which they have emerged forward
of the arcuate lugs 34. This position corresponds to the unlocked
state of the closed bolt 1.
The bolt is so designed that when it is in this state, the distance
"L" from the engagement shoulder 26 of the bolt body 3 to the
engagement surface of the catch part 6a of the cocking piece 6 is
slightly longer than the distance "1" from the shoulder 26 to the
engagement surface of the sear 36. (We have found that a suitable
difference between these distances "L" and "1" in practice is
approximately 1 mm.) Consequently, with the closed bolt in this
unlocked state, the sear 36 and the cam part 6b of the cocking
piece 6 are not in contact. This mechanical state constitutes
another important feature of the present invention.
As mentioned hereinbefore, the firing pin 4 in this state of the
bolt is being subjected to a torque due to the main spring 7 but is
being limited in rotational movement by the contact of the stop pin
16 against the rotational stop 21, whereby the engagement part 9 of
the firing pin is maintained in its horizontal position.
Furthermore, when the bolt is in this state, the elastic force of
the main spring 7 is being received by the shoulders 26 of the
engagement slot 25, with which the engagement part 9 engages, and
the annular groove 23b, with which lug 30 engages. Accordingly, the
spring force of the main spring 7 does not act on the pressure
contact surfaces of the stop pin 16 and the cocking piece 6.
The bolt of the above-described organization according to the
invention operates in the following manner.
While the bolt is in any angular position between the unlocked
state shown in FIG. 1 and the fully locked position indicated in
FIG. 2 which is reached after the bolt body 3 has been turned
90.degree. (clockwise as viewed forward from rifle butt to rifle
muzzle) from the uncocked position, the aforementioned distance "L"
is longer than the distance "1". Therefore, a gap is maintained
between the cocking piece 6 and the sear 36, which is thereby in a
mutually confronting state without any interconnection
therebetween, and the firing mechanism is inoperative.
While the bolt body 3 is thus being rotated from the fully unlocked
state to the fully locked state, the firing pin 4 is in a state of
rest, wherein the shoulders 9a of the engagement part 9 are in
engagement with the engagement shoulders 26, irrespective of the
bolt rotation. Then, when the bolt body 3 completes its 90.degree.
rotation, the engagement slot 25, which was initially vertical, is
now horizontal as indicated in FIG. 2 and is thereby in angular
alignment with the engagement part 9 of the firing pin.
During this rotation of the bolt body 3 and immediately before
completion of the full 90.degree. turn, that is, when the
engagement slot 25 reaches an angular position immediately before
it is exactly aligned with the rest position of the engagement part
9, the arcuate shoulders 9a of the engagement part 9 and the
arcuate step shoulders 26 undergo a relative rotationally sliding
motion due to the mutual action of the rotational force applied to
the bolt body 3 and the elastic force of the main spring 7 applied
to the engagement surface of the engagement part 9. As a result,
the bolt body 3 is then compulsorily rotated.
As the bolt body 3 is rotated in the above-described manner, the
locking lugs 28 at the front end thereof rotate from the fully
unlocked state as indicated in FIGS. 1 and 10 in the direction of
the arrow in FIG. 10, and the rear faces (left end faces as viewed
in FIG. 1) of the lugs 28 progressively engage with the front faces
(right end faces as viewed in FIG. 1) of the arcuate locking lugs
34 of the locking of the bolt 1 is started. Immediately before
completion of the 90.degree. turn of the bolt body 3, the bolt body
is compulsorily rotated as mentioned above, whereby the locking
lugs 28 engage fully with the front faces of the locking lugs 34.
The bolt 1 is thus fully locked. This fully locked state of the
bolt is indicated in FIGS. 2 and 13.
When the bolt 1 is thus placed in the fully locked state by
rotating the bolt body 3 through 90.degree. of angle, the
engagement slot 25 of the bolt body 3 is in angular alignment with
the rest position of the engagement part 9 of the firing pin 4.
Consequently, the engagement between the shoulders 26 and the
engagement part 9 is terminated, and the firing pin 4 is compelled
by the elastic force of the main spring 7 to advance forward
together with the cocking piece 6 through the distance of the gap
(L-l) between the cam part 6a of the cocking piece 6 and the sear
36, whereupon the cam part 6a of the cocking piece 6 engages the
sear 36 as indicated in FIG. 2.
At the same time, a part of the front extremity of the engagement
part 9 is thrust into the engagement slot 25 through a distance
corresponding to the difference L-l, whereby firing of the rifle
becomes possible. This state of the bolt device will be clearly
apparent from a study of FIGS. 12 and 14.
On one hand, while the bolt 1 is locked in the above-described
manner, the cam recess 29 at the rear end of the bolt body 3 shifts
rotationally from its position indicated in FIG. 16 to that
indicated in FIG. 17 as in a conventional mechanism of like
character. In the state indicated in FIG. 16, the front end 6c
(FIG. 5) of the catch part 6b of the cocking piece 6 is being
pressed by spring force against the rear end of the bolt body 3,
whereby the forward advance of the cocking piece 6 is being
arrested.
Then, as the bolt body 3 rotates, the cam recess 29 thereof assumes
a position as indicated in FIG. 17 in which it is confronting the
cocking piece 6, whereupon the cocking piece advances forward by
differential distance corresponding to L-l, as above mentioned, and
thereby projects into the cam recess 9 by this distance. When the
cocking piece 6 advances forward in this manner, and the catch part
6b thereof engages with the sear 36, a contact sound is emitted,
whereby the fully locked state of the bolt 1 can be confirmed.
As will be apparent from the foregoing, in accordance with this
invention, the engagement part 9 of the firing pin 4 is prevented
from advancing forward until the bolt body 3 has been fully locked
after the rotation thereof through 90.degree.. Thus, the firing
mechanism cannot be operated. It will also be appreciated that when
the bolt body is fully locked the catch part 6b of the cocking
piece 6 engages the sear 36 and firing may be effected by pulling
the trigger 40 (FIG. 1) to cause the sear 36 to retract.
The condition after firing is shown in FIG. 3, during which firing
the cocking piece 6 moves completely into the cam recess 29 as
shown in FIG. 18, and the firing pin 4 is impelled forward under
the force of the main spring 7 to cause the tip portion of the
firing pin 4 to project beyond the bolt body 3, with the stop
flange 8 engaging the shoulders 26 in the bolt body.
It will be noted that, in accordance with this invention,
accidental firing due to incomplete locking of the bolt body is
completely prevented since there is provided a "double engagement
mechanism" which allows the engagement of the cocking piece with
the sear for enabling firing only after the fully locked position
of the bolt body has been attained.
Moreover, in accordance with this invention, the resistance for
locking is considerably reduced. This is because the firing pin 4
is not rigidly secured to the cocking piece 6 as opposed to the
conventional firing pin, which was rigidly secured to the cocking
piece. Since the firing pin 4 is connected to the cocking piece 6
through the stop pin 16 and is subjected to a resilient force of
the main spring 7 urging the pin 4 rearwardly (toward the left as
viewed in FIGS. 1-3) until the fully locked position of the bolt is
attained so that the engagement part 9 engages with the shoulders
26, the cocking piece 6 is not forced against the rear end face of
the bolt body 3 until the fully locked position is reached. The
reduction of the resistance to locking is further assisted by the
compulsory locking operation as previously described.
Contrary to this, the resistance to unlocking of the bolt 1 which
has been once locked is relatively high. More particularly, because
in the locked position of the bolt the torque of the main spring 7
is acting on the engagement part 9 received in the engagement slot
25 and therefore on the bolt body 3, it is necessary to turn the
bolt body 3 against the torque of the spring 7 in order to unlock
the body 3. Thus, a relatively high resistance to unlocking is
created The unlocking resistance also serves to prevent natural
unlocking of the bolt 1 by unexpected external forces.
A further advantage of the arrangement according to this invention
is that there is no necessity for an operation such as tapping the
head of the bolt handle 24 by hand before firing for the purpose of
making sure that the bolt is in the fully locked position, this
operation having been customary heretofore in bolt action guns.
When the bolt handle 24 and therefore the bolt body 3 begin to be
turned toward the unlocked position of the bolt after firing and in
preparation for the next firing, the firing pin 4 with its
engagement part 9 engaged within the engagement slot 25 also turns
with the bolt body 3 against the torque of the spring 7 while the
engagement part 9 turns 90.degree. from the horizontal position to
the vertical position.
On the other hand, since the cam recess 29 returns to the position
shown in FIG. 16 from the position shown in FIG. 18 as the bolt
body 3 turns toward the unlocked position, the cocking piece 6 is
subjected to cam action by cam edge of the cam recess 29 and
gradually moves rearwards.
Thus, it will be appreciated that the firing pin 4 is given the
turning movement through its engagement part 9 as well as the
rearward movement through the cocking piece 6. When the bolt body 3
has completely turned to the unlocked position, the pin 16 takes
the position shown by dot-and-dash line in FIG. 9 and prevents
further rotation of the firing pin 4.
When the engagement part 9 of the firing pin takes the vertical
position as aforementioned after the bolt body 3 has completed its
rotation through 90.degree. to return to the unlocked position
shown in FIG. 1, the cocking piece 6 is moved completely out of the
cam recess 29 and the rearward movement of the firing pin 4 is
stopped. At this time, the engagement part 9 is completely free
from the engagement slot 25. Therefore, the firing pin 4 can turn
to the original position under the influence of the torque of the
spring 7 until the pin 16 contacts the rotational stop 21. In this
original position the engagement part 9 is in its horizontal
position, engaging the shoulders 26 again in the crossed
relationship to the engagement slot 25, and the bolt is fully
unlocked while the catch part 6b of the cocking piece 6 is in
spaced apart relationship to the sear 36.
The bolt 1 according to this invention as above described may be
applied to all kinds of bolt action firearms irrespective of
whether the gun is a rifle or a shotgun. In the embodiment
described, the bolt-rotating angle is 90.degree.. However, it will
be understood that a bolt-rotating angle other than 90.degree. may
be used. In all cases, however, the bolt-rotating angle must be
same as the crossing angle between the engaging slot 25 and the
engagement part 9. Further, it will be understood that the
extending direction of the engagement slot 25 is not limited to the
vertical direction as shown in FIG. 1 and may be any direction.
However, it is necessary in all cases for the rotational stop 21 to
be positioned so as to stop the rotation of the firing pin 4 when
the engagement part 9 takes a position in which it crosses the
engagement slot 25 at 90.degree..
In FIGS. 19 through 24, there are shown several modifications of
connecting means between the firing pin and the cocking piece. In
these figures, the same or corresponding parts are designated by
the same numerals as are applied to the previous figures.
In the modification shown in FIGS. 19 and 20, the firing pin 4 is
formed with an annular groove 42 at the rear end thereof, and a
resilient snap hoop or circular clip 43 engaged in the groove 42
abuts against the shoulder of a counterbore recess 14 cut in the
rear wall of the cocking piece 6.
In the modification shown in FIGS. 21 and 22, the firing pin 4 is
formed with a deep diametrical slot 44 in the rear end thereof, and
in the groove of the slat 44 there is pivoted a stop pin 45 by
means of a pivot pin 46. When the firing pin 4 is to be passed
through the cocking piece 6, the stop pin 45 is turned about the
pivot pin 46 so that it completely enters the slot 44 and is at
right angles to the position shown in FIG. 21 The stop pin 45,
after the firing pin 4 has been passed through the cocking piece 6,
is returned to the position shown in FIG. 21 and is brought into
engagement with the shoulder of the recess 14.
In FIGS. 23 and 24 there is shown a further modification in which
the firing pin 4 is formed with a diametrical slot 44, and a stop
pin 47 is pivoted at one end thereof at 48 within the slot 44 and
urged counterclockwise as viewed in FIG. 23 against the side wall
of the recess 14 by means of a compression spring 49. When the
firing pin 4 is to be passed through or to be removed from the
cocking piece 6, the stop pin 47 is depressed into the slot 44
against the force of the spring 49.
In the three modifications shown in FIGS. 19 through 24, no such
rotational stop as shown in FIGS. 9 and 11 and designated by the
reference numeral 21 is provided. However, any suitable means
functioning as stop means may be provided. However, any suitable
means functioning as stop means may be provided in lieu of the stop
21 in these modifications.
In FIGS. 25 and 26, there is shown a still further modification of
the connecting means for the firing pin and the cocking piece. In
this modification, a transverse cutout 51 is provided in the middle
part of the cocking piece 6 through 270.degree. so as to leave a
connecting portion 52, and a stop pin 54 is removably inserted
through the portion of the firing pin 4 located in the cutout 51.
The connecting portion 52 serves as a stop for the pin 54. The
cocking piece 6 is covered by a cup-shaped casing 50 having a pair
of diametrically oppositely arranged holes 53 through which the
stop pin 54 may be inserted into and removed from the firing pin
4.
* * * * *