Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to firearms, and in particular to an
actuating mechanism for a firearm. The invention is especially
but n~t exclusively concerned with self~loading firearms capable
of firing a number of rounds in rapid succession, and these rounds
may comprise projectiles in the form of, for example, so called
rubber bullets, grenades, or other fragmentation devices, or
gas canisters.
In conventional practice the round to be fired comprises a
projectile and a cartridge case containing a quantity of explosive
which can be initiated by operation of the firearm to provide the
energy necessary to eject the projectile from the barrel of the
firearm with considerable velocity. The cartridge case is
conventionally rather weak mechanically, and at the time of
firing it must therefore be supported by being fully inserted
into a chamber in which it fits closely to receive mechanical
support from the chamber wall. From this necessity it has
followed that any self-loading mechanism must be capable of first
moving each round in turn laterally into alignment
with the chamber, and then longitudinally through a relatively
long stroke sufficient to achieve fuIl insertion of the
cartridge case into the chamber. This requirement has caused
a number of constraints on the freedom of the designer.
The pre~ent applicant has appreciated the possibility
that in some instances a round might be fired in a partially
supported or a substantially unsupported state, ie without the
necessity for the cartridge case to be fully inserted into a
supporting chamber. A relatively small forward motion of the
round after alignment with the barrel may still be necessary,
in order to ensure positive location of the round prior to
firing, but the stroke can be very considerably shorter, and
this opens the possibility of a novel and considerably simpli-
fied actuating mechanism, which is also capable of ensuring the
small forward movement of the round which may be necessary
before firing takes place.
Conventional practice has also been that, following
the initial cocking of the weapon~ the energy necessary to
operate a self loading mechanism for chambering successive
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rounds has been derived in each firing.cycle from the energy
release by firing the previous round. Thus,'for example either
the re-coil energy has been harnessed for this purpose, or some
of the energy present in the gases generated on firing has ~een
used. It has been necessary to provide relatively complex
devices for energising the self-loading mechanism in these ways.
It is a feature of the actuating mechanism of the present invention
that the cocking of the firing pin and any longitudinal movement
required of each fresh round fed into place is energised by
manual operation of the trigger mechanism itself, thus providing
the possibility for considerable simplification of design.
According to the present invention, an actuating mechanism
for a firearm having a body and a breech comprises
a breech block slideable longitudinally relative to
the body of the firearm and having a forward breech
end for engaging and pushing forward a round of
ammunition in the breech;
a firing pin slideable longitudinally relative to the
body and to the breech block;
resilient means which can be stressed by forward
movement of the breech block relative to the firing pin;
detent means engageable with the firing pin to prevent
longitudinal movement of the firing pin relative to the
body of the firearm;
2S and a toggle mechanism comprising first and second tog-
gle bars and forming at least a part of an operative
linkage between a trigger and the breech block;
the first toggle bar bein~ pivotally connected at a
first pivot point to the breech block, the second toggle
bar being pivotally connected at a second pivot point
to the body of the firearm said first pivot point being
forward of said second pivot point, and the first and
second toggle bars being pivotally connected together
at a third pivot point,'the trig~er being operatively
linked with the toggl'e mechanism wh,ereby initial
operation of the trigger moves the third pivot point
towards alignment with the first and second pivot points
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so that the breech block is moved forwards and the resilient
means is stressed, and whereby further operation of the trigger
moves the toggle mechanism over centre to lock the breech block
forward ~nd releases the detent means.
Advantageously the detent means comprises a sear engage-
able in a bent in the firing pin, and a mechanical connection
is operative between the toggle mechanism and the sear to dis-
engage the sear from the bent after the toggle mechanism is
moved over centre.
The mechanical connection conveniently comprises a sear
release pin slideable transversely in the ~iring pin so ~hat one
end of the pin can contact the sear and the other end of the pin
can contact the toggle mechanism, the length of the pin being
such that when the toggle mechanism moves over centre it pushes
the pin against the sear to disengage the sear from the bent.
Advantageously, the firearm comprises a magazine from
which a fresh round of ammunition can be supplied to the breech
on removal of the case of a spent round.
The magazine can be a rotary magazine comprising
a magazine body defining around part of its circumference
an opening through which a round of ammunition can be
inserted or withdrawn, and around a remaining part of
its circumference defining a circumferential restraint
through which a round cannot be inserted or withdrawn;
2~ a carrier rotatable within the body about a carrier axis
and having radially extending portions adjacent pairs o~
which define positive locations in which a round of
ammunition can be accommodated on insertion through the
.opening, rounds being slideable longitudinally in said
positive locations;
resilient carrier biasing means for urging the carrier to
rotate in a particular bias direction;
a guide member moveable across the opening;
. said.guide member having a guide surface facing against
the bias direction so that ~ round inserted through the
opening is guided thereby into one of s~id positive
locations.and simultaneously rotates the carrier against
its bias;
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said,,guide member having a round~retaining sur~ace facing
towards the bias direction which can co-operate with one
of the positive locations to positively retain the first-
inserted round against circumferential and radial mo~e-
ment;, and
restraining means fo,r holding the guide member in a
position such that the guide surface faces the opening
whenever the carrier occupies a position corresponding
to one in which the m~gazine contains less rounds of
ammunition than its maximum capacity, the guide member
being moveable against the bias direction during movement
of the carrier corresponding to insertion of the final
round so that the first-inserted round may then pass
through the position occupied at other times by the guide
means.
Alternatively the magazine can be of a form in which one
or more rimmed rounds of ammunition may be stacked each in contact
with an adjacent round the firearm comprising
resilient ma~azine bias means;
a breech opening through which a round of ammunition may
be inserted into the magazine, the breech opening defining
transverse guide means through which a round can be
inserted in a direction transverselv of the barrel axis
against the action of the magazine bias means, and re-
straining means which are effective on subsequent forward
movement of the inserted round to restrain the round in
the breech against the action o the magazine bias mPans;
a catch which can assume a locking position in which it
prevents return of a round forwardly located in the breech
to a position in which it can re-enter the transverse
guide means;
further guide means by which a round in the breech can be
guided in a direction trans~ersely o~ the barrel axis and
rearwardly into the magaz.ine against the magazine bias
means on insextion of a further round into the breech;
the catch being effective to keep separate the rims of one
round and a subsequently inserted round during the 'inser-
tion of the subsequently inserted round, whereby the
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subsequently inserted xound when engaged in the breech
has its rim in front of t~e rim of the said o~e round.
The invention will now be described by way of e~ample
only with reference to the accompanying drawings, of which
Figure 1 is a side elevational view on the line I-I of
Figure 2 of a first embodiment of firearm in accordance
with the invention, Figure lA shows a part of Figure 1
to an enlarged scale;
Figure 2 is a plan view,-part in section of part of the
firearm shown in figure 1;
Figure 3 is a sectional end elevation on the line III-
III of figure lA;
Figure 4 is a sectional end elevation on the line IV-
IV of figure 2;
Figure 5 is a sectional part view on the line ~-V of
figure 4;
Figure 6 is a sectional part view on the line VI-VI of
figure 3;
Figure 7 is a sectional part view on the line VII-VII
of figure 3;
Figure 8 is a side elevational view of a round of
a~munition suitable for use in the firearm of figures
1 to 7;
Figure 9 i5 an end elevational view of the round of
ammunition shown in figure 8,
Figure 10 is a sectional elevational view of a second
embodiment of firearm in accordance with the invention,
also intended to use rounds of ammunition of the type
. shown in figures 8 and 9;
Figure lOA shows a part of Figure 10 tO an enlarged
scale;
Figure 11 is a plan view, part in section, of part of
the firearm of figure 10; and
Figure 12 is a sectional view from below of a loading
catch forming part of the ~irearm of figure 10.
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~ s seen in Figures 1 to 7, a self-loading fireaxm comprises
a barrel 1, a rotating magazine assembly 2, a firearm body 3
housing a breech block and firing mechanism, a butt assembly 4
and a pistol grip 5. A trigger 6 is pivoted at 7 in the base
5 of the pistol grip 5, and is biased to rotate anticlockwise about
the pivot 7 by means of a double leaf spring 8 stressed against
the rear of the pistol grip 5. A trigger guard 9 protects the
trigger against accidental oper~tion.
Pivoted at 10 to the forward upper portion of the trigger
10 is a link member 11, which extends generally rearwardly from its
pivot point 10. Pivotally fixed at a pivot point 12 to the rear
end of the link member 11 is a rearward extension of a first
toggle bar 13. Toggle bar 13 is pivotally connected at its forward
end by pivot 14 to a breech block 15 slideable longitudinally in
15 the body 3. Pivotally connected by a pivot 16 to an intermediate
point on the first toggle bar 13 is a second toggle bar 17 which
extends rearwardly from the pivot 16,and is itself pivoted by a
pivot 18 to the body 3.
Slideable longitudinally within a channel 19 in the breech
20 block 15 is a firing pin 20 having a hardened forward tip portion
20A, and a side cheek 20B which can bear on a pin 21 held captive
in a transverse bore in the body 3.(Fig.2)
A strong helical compression spring 22 provided with a
thrust cap 23 is located rearwardly of the firing pin 20 in the
25 bore 19 between a retaining pin 24 and a shoulder 25 of the bore
19. A relatively weak helical return compression spring 26 is
also located in the bore 19 between a forward-facing shoulder 27
on the firing pin 20 and a shoulder 28 of the bore 19.
A sear 29 pivoted to the body 3 by pivot 3G is urged to
30 turn clockwise (as viewed in Figure 1) about the pivot 30 by a
spring 31, towards engagement with the firing pin 20. The tip
of the sear 29 can engage, through a longitudinal slot 32 in the
breech block 15 with a bent 33 on the firing pin 20, to restrain
the firing pin from forward movement. A sear control pin 34 of
35 generally cylindrical form can slide in a transverse bore 35 in
the firing pin 20. The pin 34 has a flat 36 formed on its lower
portion, but not extending to its lower end. The width of the
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pin 34 at the section of the flat 36 is such as to permit t~at
section of the pin to slide alo~g a lon~itudinal slot 37 in, the
breech block 15 which.is of a Width less than the full diameter
of the pin 34. The length of the flat 36 in the direction of the
5 pin axis is such as to permit a limited sliding transverse movement
along the bore 35, but escape of the pin 34 is prevented by abut-
ment of its full diameter portions against the edges of the slot
37. During assembly, the pin enters the slot 37 through a key-
hole 38 in the breech block l9, but during normal operation of the
10 firearm the relative movement of ~he ~iring pin 20 and the breech
block 19 is limited so that the pin 34 does not become aligned
with the keyhole 38.
The magazine assembly 2 comprises a magazine body 40 and
a spindle 41. The spindle is secured to the,firearm body 3 by
15 means o a screw 42, and the magazine body 40 is secured to the
spindle by means of a screw 43. A spigot 44 on the body 40 locates
within a corresponding socket on the body 3 and correct alignment
is ensured by an alignment pin 45 (Figure 2) secured to the body
40 and fitting closely within a corresponding alignment recess
20 in the body 3. Mounted for rotation on the spindle 41 is a star
wheel assembly comprising a forward star wheel 46 and a rearward
star wheel 47 locked to rotate together by means of dogs. The
star wheels 46, 47 are of mutually similar transverse cross-
section as best seen in Figures 3 and 4, each comprising res-
~5 pectively five evenly spaced radially-extending arms 48, 49 shaped
to define a slightly less than semi-circular recess 50, 51 between
each adjacent pairs of arms, the recesses of the two star wheels
being axially aligned with one another. The star wheel assembly
~6, 47 is urged to rotate in a clockwise direction as viewed in
30 Figure 3, by means of a pair o~ helical torsion springs 52, 53
mounted axound the spindle 41. At their forward end, the springs
52, 53 have tails which bear against a cross-pin 54 to restrain
rotation around the spindle. At their rearward ends~ the springs
5~, 53 ha~e tails which engage in corresponding holes in the forward
35 face of the stax wheel portion 47. Thus when the star wheel
assembly ~6, 47 is turned anticlockwise (as viewed in Figure 3)~
a torsional restoring force is provided by springs 52, 53.
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cert~in degree o~ torsion is impqrted to the springs 52~ 53
during assembly so that they bias the star wheel assembly to
turn clockwise as viewed in Figure 3O
Each arm of the star wheel 47 is provided with a rearwardly
projecting tail 55 which runs freely, as the star wheel rotates,
in an annular recess 56 in the adjacent end face of the body 3.
As seen in Figure 5, a catch 57 having a slotted pivotal mounting
58 in the body 3 is urged forwardly by the action of a spring
loaded plunger 59, the forward movement of the catch being limit-
ed by a stop pin 60. The catch 57 has a hooked portion 61 adapted,when in its forward position, to engage and restrain an adjacent
tail 55. The catch 57 also has a cam face 62 engageable by the
outer end of the pin 21.
A loading arm 63 is provided comprising a pair of curved arms
G~, 65 freely pivoted respectively on the spindle 41 just ahead
of the star wheel 46, and on a boss formed on the forward portion
of the star wheel 47. The arms 64, 65 are linked rigidly to- ~.
gether by a longitudinally extending guide bar 66.
Referring particularly to Figures 3, 6 and 7, a floatin~
pin 68 received in a longitudinal bore in the forward curved arm
64, where it is held captive between the front face of the star
wheel 46 and the rearward face on the body 40. As shown, the
forward end of the pin 68 is received in a curved depression 69
in the forward face of the body 40, and the rearward end of the
pin 68 is received in an annular grove 70 in the forward face
of the star wheel 46. A cross pin 71 fixed by adhesive in a
radial bore in the star wheel 46 extends across the groove 70
and acts as a stop to prevent the star wheel assembly 46, 47
making substantially more than a single revolution relative to
the loading arm 63.
The pin 68 is of a greater length than the depth of the
groove 70.plus the thickness of the forward curved arm 64, so
that normally the pin 68 projects into the depression 69 so that
the loading arm 63 is lockad statio~axy with the bod~ 40, while
the star wheel assembly can rotate relative thereto, the ~roove
70 providing `clearance fox the pin 68.
A conical depressio~ 72 is provided in the base of the groove
70, adjacent the cross pin 71. When the star wheel assembly ~6,
,;
47 has completed almost a full revolution relative to the body
40 from the positiQn illustrated~ the end of the pin 68 wi~hin
the groove 70 can enter the depression 72, which is of sufficient
depth to enable the other end of the pin 68 to clear the de-
5 pression 69. The loading arm 63 can then move relative to thebody ~0 between limits set by an opening 73 for the insertion
o~ rounds of ammunition therein, the disengagement of the pin
being ~acilitated by the curved shape of the depression 69.
During this movement the star wheel 46 and the loading arm 63
10 are locked together by the pin 68.
The round of ammunition for which the firearm is designed
is shown in Fig~lres 8 and 9. It comprises a cylindrical case
74 which contains a projectile (not shown) such as for example
~a so-called rubber buIlet. The round is also provided with a
15 projecting rim 75 at its rearward end, and in the rearward face
76 there is provided a percussion cap 77 by which the rounds may
be fired. The case is designed so as to be substantially self-
supporting, ie insertion into a supporting chamber to prevent
rupture of the case when the round is fired is unnecessary.
Rounds may be inserted into the magazine through the opening
73. Entry of a fresh round is facilitated by a recessed portion
78 on the forward face of the magazine body 40, bounded by a
chamfered portion 79. After insertion through the opening, a
round is located in a corresponding pair of recesses 50/ 51 which
25 provide a positive location therefor in the star wheels 46, 47.
As the star wheel assembly is rotated, the forward end of the
casing 74 is restrained from radially outward movement by a part-
circular rim 80 which extends around the whole of the forward
face of the body 40 with the exception of the region of the open-
30 ing 73 ~see Figure 3). At the rear endl the casing is restrainedfrom radially outward movement by an arcuate rim 81. The casing
is restrained from axial movement around the whole circumference
of the body except the region of the opening 73 and the breech
region, by a radially inwardly directed lip 82 behind which the
35 rim 75 locates. In the region. o~ the breech, the round is re-
strained axially by a lip 39.on the breech b~ock 15. The concave
surfaces of the curved arms 64,65 of the loading arm 63 are
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approximately semi-circular for a reaso~ explained hereinafter,
the radius being approximately equal to that of the casing 74.
The barrel 1 is provided at its breech end with a very
short chamber in the form of a socket portion 83 in which the
5 forward end of a round can be received. The socket portion 83
has a shouIder 84 which the round cannot pass, and entry to the
~hamber is facilitated by a short cham~ered section 85.
In use of the firearm, any number of rounds up to five
may be placed in the magazine by successive insertion through
10 the opening 73. As the first round is inserted, its entry is
facilitated by the recess 78 and cham$ered portion 79. The
loading arm 63 is locked by the pin 68 in the position illustrated.
The loading arm hence cannot pivot to a position where it hin~ers
entry of the round. As the round is pressed inwardly into
lS position the arms 64, 65 guide the round so that it moves also
in an anticlockwise direction (as viewed in Figure 3), towards
alignment with the barrel, ie towards the breech position. The
casing 74 of the round thus bears on the arms 48, 49 of the star
wheels 46, 47 to move the star wheels anticlockwise (as viewed
20 in Figure 3), against the torsional bias of the springs 53, 54
until the round is fully received in a correspondiny pair of
recesses 50, 51. As the round xeaches the position where it is
aligned with the barrel 1 the hook 61 of the catch 57, under the
action of the spring-loaded plunger 59, snaps into place behind
25 the tail 55 of an arm 49. The star wheel assembly is hence held
in this position against the bias of the springs 53, 54 by a
ratchet action of the catch 57, with the round in the breech
aligned with the barrel.
A second, third an~ fourth round may be inserted in
30 exactly the manner described above. As the rounds move around
the m~gazine they are restrained inwardly in the recesses 50, 51
of the star wheels 46, ~7 and outwardly by rims 80, 81 whilst
longitudinal movement of the rounds is restrained by lips 39 and
82 engaging rims 75.
However/ when it is desired to insert a fifth round,
the loading arm obstructs the path of the first round. This
difficulty is oyercome as follows. As the fifth round is in-
serted, the star wheel 46 moves to the position in which the
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2 5 6
recess 72 comes into alignme~t with the pi~ 68. As the first
round pushes against the loading arm, the pin 68 is urged by
the camming action of the curved surface of the depression 69
to move into recess 72 so that the loading arm becomes simul-
taneously unlocked from the magazine body 40, and locked insteadwith the star wheel 46. Hence as the action of inserting the
fifth round continues, the first round moves round into the
opening 73. However, the first round is prevented from escaping
through the opening 73 by the loading arm 63 locked to the star
wheel 46 so that the semi-circuIar recesses 50, 51 together with
those of the arms 64, 65, enclose the round over about three-
quarters of its circumference.
When the trigger 6 is pulled with the magazine 2
loaded, the action is as follows. The link member 11 is moved
rearwards and is hence forced to pivot anticlockwise (as viewed
in Figure 1). The pivot 12 is thus forced to move upwards, so
that the toggle mechanism comprising the first toggle bar 13
and the second toggle bar 17 begins to straighten. The breech
block 15 is hence moved forward by virtue of the pivotal connec-
tion 14, carr~ing with it a round positively engaged behind thelip 39. As the breech block moves forward, the round slides
longitudinally through its recesses 50, 51 to locate in the
socket 83 in the barrel 1.
As the breech block moves forward, the firing pin 20
is held on the sear 29, so that the spring 22 becomes compressed
between the firing pin 20 and the retaining pin 24. When the
toggle mechanism 13, 17 reaches its fully straightened position,
the round is fully engaged in the socket 83 and the breech
block is safely locked against rearward movement. A small
further trigger movement brings the toggle mechanism to a posi-
tion where it is locked slightly over-centre with the upper
surface of the second toggle bar 17 bearing on the pin 34 and
pushing it upwards to disengage the sear 29 from the firing pin
20. The firing pin then shoots forward under the action of
the spring 2?, until it reaches the position shown in Figure 1,
where the thrust cap 23 bears on the shoulder 25. Thereafter
the firing pin continues forward at high speed, under its own
inertia, so that its hardened tip 20A strikes the percussion
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cap 77 to fire the round. It will be noted that the casin~ of
the round is almost totally unsupported at the time of ~iring.
As the firing pin moves forward, it compresses the
return spring 26 between the shoulders 27 and 28. As the firing
pin approaches the firing position, the cheek 20B contacts the
pin 21 and forces it outwards by a camming action on to the side
surface of the firing pin 20. The outer end of the pin 21 now
projects in front of the cam face 62, but only if the firing pin
has shot fuIly forward to fire the round.
As the trigger ~ is released, it returns under the action
of the leaf spring 8, the toggle mechanism 13, 17 is pulled down
by the return of the link 11, and the breech block 15 is hence
drawn back towards its original position, taking with it the
iring pin 20, and the spent case of the fired round which is
held by the lip 39.
During this return movement the firing pin remains in
a forward position relative to the breech block (although re-
tracted clear of the front face of the breech block by the spring
26). The pin 21 is thus held outwardly during the return move-
ment by contact with the flank of the firing pin. As the breechblock moves back, the pin 21 bears on the face 62 of the catch
57, to pull the catch backwards and disengage the hooked portion
61 from the adjacent tail 55. The star wheel assembly 46, 47 is
thus freed from the catch 57 which now moves downwardly in its
slotted pivot to clear the pin 21 and snap into position ready
to catch the next succeeding tail 55. The star wheel assembly
46, 47 is restrained from rotation under the action of the springs
52, 53 until the spent case has cleared the socket 83 and the
chamfered portion 85, and the breech block has cleared the star
wheel ~7. When this stage is reached, the star wheel assembly
is freed to index forward under the action of the springs 52, 53
until the catch 57 engages the next succeeding tail 55. The
spent case is thus automatical~y ejected through the opening 73,
and the next round (if any) in the ma~zine i5 automatically
indexed around into alignment with the breech block 15 and the
socket 83 where it is ready to ~ire. It shouId be noted, however,
that this sequence can occur only if the firing pin 20 has been
released and moved forward to fire a round, thus countering the
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possibility of a live round being accidentally ejected.
When the breech is fully retracted the sear 29 moves
under the bias of the sear spring 31 into engagement once more
with the bent 33 on the firing pin.
As long as the magazine contains another round, the
sequence can be repeated and all of the rounds in the magazine
may thus be fired in rapid succession by repeated operation of
the trigger.
If it is desired to remove rounds from the magazine with-
out firing, this may be achieved by manually depressing the tail
(visible in Figures 2 and 5) of the catch 57, whereupon the star
wheels 46, 47 are released and t~e rounds are ejected automati-
cally in sequence in similar manner to the ejection of rounds
when spent. Further rotation of the star wheel assembly could
lS release all torsional pre-stress in the springs 52, 53 and so
detract from subsequent proper functioning of the magazine ~ed.
This is prevented by the pin 68 coming against the cross pin 71
just after the last round is ejected.
The embodiment o~ the invention shown in Figures 10 to 12,
comprises a body 101 integral with a barrel 102, a magazine
casing 103, a pistol grip 10~ and an adjustable butt 105. The
magazine casing 103 and pistol grip 104 are formed integrally
as a steel pressing, and a trigger guard 106 is welded thereto.
This assembly is attached under an opening in the body 101 by
a tail 107 on the pistol grip and a transverse pin 108 passing
through a forward projection (not shown) on the magazine casing.
The magazine casing 103 houses a wire spring 109
positioned in the base of the casin~ by riveted pins 110. Carried
on the top of the spring 109 is a magazine platfor~ 111 having
an upper surface of semicylindrical general form. The platform
111 is hollow and can accommodate the compressed spring 109
when fully depressed into the casing 103.
An opening 112 is proYided in the upper surface of the
body lOl above thé magazine casing, through which rounds of the
type shown in Figures 8 and 9 may be inserted. A groove 113
is prQvided in each side walI of the ~pening to accommodate
the rim 75, the adjacent wall portions near the upper edge of
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the opening 112 constituting cheeks 114 between which the
cylindrical casing 74 of a round may pass, but the rim portion
75 may not. Below the cheeks 114, the opening widens to permit
entry of a rim 75~ At the foxward end of the opening 112, the
rearward end of the barrel 102 has an upper overhanging portion
115 beneath which the forward end of a round may be held, and
a lower chamfered portion 116 which can guide a round downwards
and rearwards into the magazine c~sing 103. The rearward end of
the barrel also has a socket 117 constituting a short chamber
into which the forward end of the casing 74 may be engaged prior
to firing.
A loading catch 118 is pivoted at 119 in the steel
pressing 103,`104 and is biased clockwise (as viewed in Figure
10) by a spring 120. The loading catch 118 has a pair of limbs
121 which extend forwards into the opening 112, a pair of limbs
122 which extend rearwardly, and is provided with an arcuate
depression 123 in its upper surface.
The rear portion of the body 101 is of generally cylin-
drical form, and a cylindrical portion of the adjustable butt
105 is slideable longitudinally therein so that the butt length
may readily be adjusted to suit the user. The adjustable butt
may be locked in a desired position by insertion of the butt
locking pin 124 through holes provided in the body 101 and the
~5 butt 105.
Slideable longitudinall~ in the body 101 in front of
the butt 105 is a breech block 125 of generally cylindrical form.
Slideable longitudinally within respective bores 126 and 127 in
the breech block 125 are a firing pin 128 and a sear block 129.
The iring pin can be biased forwardly relative to the breech
block by a firing pin spring 130 having a thrust washer 131 at
its forward end. The forward movement of the spring 130 is
limited by the washer 131 coming into contact with a shoulder
133 in the bore 126. The spring`l30 is held within the bore
126 at its rearward end by a cross pin 132 located at the rear
end of the breech block. A relatively weak firing pin re~urn
spring 134 acts between a shoulder 135 and the bore 126 and a
shoul~er 136 on the firing pin 128, to urge the iring pin rear-
wards.
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The sear block 129 is urged forward by a sear spring 137
whose rearward end also reacts against the cross pin 132. Pivoted
on a transverse sear pivot 13~ wit~in a longitudinal ~lot in
the sear block 129 is a sear 139. The sear has a bent on its
5 upper edge which en~ages with a transverse pin 140 located in
the body 101. The sear also has a nose which can engage with a
bent 141 in the firing pin 128. A sear pin 142 is slideable
vertically in a bore which passes through the firing pin beneath
the sear bent. The sear pin 1~12 is of generally cylindrical
10 form, but has a reduced diameter portion 1~3 which can slide
longitudinally within a longitudinal slot 144 in the breech
block 125. During assembly, the pin 142 can enter the slot 14~
through a keyhole 145, but cannot escape therefrom during normal
operation of the firearm. The pin can move vertically between
15 limits determined by the length of the reduced diameter portion
and the depth of the slot 144.
Pivoted to the breech block 125 at 1~6 is a first toggle
bar 147. Pivoted to the bo~y 101 at 148 is a second toggle bar
149. The first and second toggle bars are pivoted to each othex
20 at 150 to constitute a toggle mechansim, which is biased down-
wardly by a toggle spring 151.
A trigger 152 is pivoted at 153 to the pistol grip 104,
the pivot being retained by spring clip 154. The upper surface
of the trigger is formed in the shape of a V, and the lower
25 surface of the second toggle bar bears on the rearward arm>~ of
the V.
A pin 155 has an enlarged head 156 by which it is held
captive in a stepped bore 157 in the breech block 125, which
boxe 157 is angled forwardly and down from the bore 126 through
30 to the exterior of the breech block. The pin 155 is pre~ented
from escaping upwardly and rearwardly from the bore 157 by
contact with t~e underside of the firing pin 128. When the
firing pin is in a rearward position relative to the breech
block 125, the head l56 thereof can retxact into a cam slot 158
35 in the forward underside of the firing pin, so that the lower
end of the pin 155 can retract into the breech block. As the
firing pi~ ~ears its most ~orward position relative to the
-16-
the breech block, an arcuate portion of the cam slot 158 pushes
the pin 155 downwards so that it projects from the bxeech block.
As shown in Figure 11, a floating extractor 159 has an open
slot 160 therein by which it is held by means of a transverse
pin 161 fixed in the breech block 125. The extractor 159 can
slide longitudinally relative to the breech block in a groove
16~ in the body 101 and a groove 163 in the side of the breech
block, and can also pivot on the pin 161 to an extent permitted
by the space available between the grooves 162 and 163~ The
extractor is urged for~ar~ly by an e~tractor spring 164 engaged
in a recess 165 in the breech block ~n-d acting through a plunger
166. The plunger 166 bears on a flat rear face of the extractor,
which is so angled that the forward end of the extractor is
biased towards a position somewhat inwards from the groove 162.
The extractor 159 has an inwardly-directed hook 167 at its
forward end and a small inwardly-directed projection 168 at its
rearward end. A short pin 169 fixed in the body 101 projects
into the groo~e 162 to obstruct movement of the extractor for-
wards therein beyond the pin.
A pin 170 is slideable transversely in a bore in the breech
block which opens into the bore 126 and the groove 163. When
the firing pin occupies a forward position relative to the
breech block, the inner end of the pin 170 bears on the flank
of the firing pin, so that the outer end of the pin 170 is forced
to project into the groove 163. When the firing pin occupies
a rearward position relative to the breech block, a recess 171
in the flank of the firing pin comes opposite the pin 170 so
that it can retract from the groove 163.
The firearm is loaded by inserting a rimmed round of the
type shown in Figures 8 and 9 in through the aperture 112, with
the rim passing down through the grooves 113 and the forward end
of the round passing behind the overhanging portion 115. This
action depresses the mag~zine platform 111 and compresses the
spring lO9, and also as the rlm 75 bears on the limbs l~i, the
loading catch 118 is depressed about its pivot. ~s the rim
clears the cheeks 114, the round is given a forward movement so
that the rim passes below the cheeks, and the forward end of the
2 5 ~)
-~7-
round passes under the overhanging poxtion 115. This frees
the limbs 121 from under the rim 75 so that the loading arm
springs up behind the rear face 76 of the round to prevent the
round being drawn back again. The round is thus held captive
under the overhang 115 a~d the cheeks 114, in alignment with
the barrel 102. The round may now be fired as described here-
inafter, or alternatively a second round may be inserted in the
same way as the first.
It will be observed that when a second round is inserted
through the opening 112, its rim wi~l occupy a position behind
that of the first round. For reasons which will become more
clearly apparent hereinafterr tke feeding of rounds from the
magazine back to the firing position in the breech will be
obstructed if the rounds are stored in the magazine with the
rlm of a second-inserted round behind that of the first. Accord~
ingly it is~an important function of the loading catch 118 that
it ensures that the first-inserted round enters the magazine with
its rim behind that of the second.
This is achieved as follows. The second round is inserted
on top of the first round with its rim in groo~es 113. As the
second round is pushed down the first round is guided downwards
and rearwards by the chamfer 116. At this point the rim of the
second round depresses the loading catch 118 on to the rim of
the first round, thus enabling the second round rim to pass over
the rim of the first round when pushed forward engaging under
the cheeks 114. As the second inserted round moves down and
forward, the loading catch 118 snaps up behind it, locking the
second round forward in the breech in the same way as the first.
The first round now occupies a position in the magazine casing
with the second round resting on top of it and holding it down
against the spring 109, the rim of the second in front of that
of the first.
The second round may now be fired as described hereinafter,
or a third round may be inserted in the same way as the second.
If a third round is inserted~ the final position will be with
the first and second rounds in the magazine, biased upwardly
by the spring lO9, and the third round xesting on top of the
. . . ~., ,: .
:,
~ .
:: ~ 642~
-~8-
second and holdin.~ it down. The third round will be in the
breec~ its forward end under the overhanging portion 115, its
ri~ under the cheeks 114, and the arms 121 preventing its escape
rearwards. The rim of the third round will be in front of the
5 rim of the second round.
When the trigger 152 is pulled against the pistol grip 104,
it pivots rearwardly about the pivot 153. The upper surface of
the trigger bears against the second toggle bar 149, forcing it
upwaxds and so straightening the toggle mechanism comprising the
10 toggle bars 147, 149. As the toggle mechanism straightens, the
breech block 125 is pushed forwards, but the firing pin 128 is
restrained ~rom forward movement by engagement with the sear 139.
~s the breech block moves forwards f the spring 130 is compressed
between the pin 132 and the firing pin 128, and the spring 137 is
15 comp~essed between the pin 132 and the sear block 129 held on the
pin 140. If there is a round in position aligned with the barrel,
forward movement of the breech block also pushes the round in~o
positive engagement in the socket 117,- the rim of the round
sliding on the chee~s 114 against which it is held by the bias
20 of the spring 109. As the round nears full engagement in the
socket 117, the toggle bars 147, 149 reach the straight position
and pass slightly over centre to lock the breech block 125
positively in a forward position. At the same time the upper
surface of the first toggle bar 147 contacts the pin 142 and
25 pushes it upwards to disengage the sear 139 from the bent 141 on
the firing pin 128. The firing pin is thus freed to shoot for-
ward at high speed under the action of the spring 130, and
strike the percussion cap 77 of the round to fire it. It will
be observed that in the position illustrated the spring 130 rests
30 on the shoulder 133 ( via the washer 131), but the tip of the
firing pin remains within the breech block. The firing pin thus
completes its forward movement under its own inertia, compressing
the li~ht restoring spri~g 134. ' The-spring 134 then retracts
the firing pin immediately ~ftex firi~ng so that its tip lies
35 within the breech block cle~r of t~e percussion cap 77, where
it cannot interfere with ejection of the spent case. When the
trigger is relea~sed after firing,Ithe togg'le mechan.ism is
. ~ . -. ~ ..
3 1~2~
-19-
pulled back from its over-centre position b~ the ~pring 151, and
the breech b~ock is retracted by the spring 137 compressed
betwee~ ~he-pin 132 and the sear block 127.
The extractor claw 159 is effective only when a round is
5 present in the breech. At other times,-the forward end of the
extractor is angled imwardl~ under the bias action of the spring
164 on its rear face, so that it always clears the pin 169, and
simply moves back and forth in unison with the breech block 125.
When the extractor 159 is thus angled inwardly, the projection
10 168 can clear the pin 170 even when the pin 170 is fully extended
by contact of its inner end with the f~ank of the firing pin 128.
When a round is introduced in front of the breech block
125, however, the rim 75 thereof contacts the extractor behind
the hook 167 to push its forward end outwardly into the groove
15 162. In this orientation,-the projection 168 cannot clear the
pin 170 when fully e~tended by contact of its inner end with the
flank of the firing pin, and forward movement of the extractor
is limited by contact with the pin 169.
When the trigger is operated with a round in position in
20 front of the breech block, the extractor 159 moves forward with
the breech block 125 until the extractor contacts the pin 169.
As the breech block moves forward further, the extractor is
prevented from doing so, and the pin 161 slides along the slot
160 in the extractor, the rear end of the extractor bearing on
25 the plunger 166 to compress the spring 164. At this stage of
the firing sequence, the firing pin 128 is held to the body 101
by the sear 139, and hence it cannot move with the breech block.
Thus as the pin 170 comes adjacent the projection 168 the pin
170 can retract into the recess 171 in the firing pin to clear
30 the projection. When the firing pin is freed from the sear,
the flank of the firing pin once again contacts the inner end
of the pin 170 to hold it locked fully outwards, but now the
pin 170 is in front of the projection 168. As the breech block
and firi~g pin are retracted by the sp~ing 137 on release of
35 the triggerr the extractor is thus held to the breech block by
the pin 170 engaging in front of the projection 168. 5ince the
rim of the round is caught behind the hook 167, the spent case
. .
2 ~ ~
-20-
is withdrawn with the breech block until it clears the cheeks
114 and comes into line with the slots 113. The loading catch
118 is held down to permit this extraction to occur, as explained
hereinafter. When the rim clears the chee~s 114 there is no
5 influence restraining the spent case against the bias of the
spring lO9, and the spent case is thus ejected automatically
through the opening 112. It will be appreciated that if the load-
ing catch were not held do~n during this extraction sequence the
upper and lower round are held in contact with one a~other by the
10 spring 109. However, because it is h~ld down the loading catch
118 itself in turn holds down the ~ower round so that the rim of
the upper round can slide rearwardly and upwardly over the upper
surfaces of arms 121, thus clearing the lower rim. The function
of the loading catch is thus seen to be an exceedingly important
15 one. In its absence, the spent case wouId be prevented by contact
o~ its rim with the rim of the lower round, from retracting fully,
and hence could not be ejected.
As soon as the spent case is ejected, the forward end of the
extractor is free to move inwards under the influence of the spring
20 164 and the plunger 166 on its rear end. The resulting small
rotation of the extractor is sufficient to enable the projection
168 to clear the pin 170 so that the extractor snaps back immed-
iately (ie before the next round can rise into the breech to
obstruct the forward movement of the extractor) to its forward
25 position relative to the breech block, as shown in Figure 11.
In order to permit extraction of the spent case, the loading
catch 118 must be held down whilst the case is moved rearwards.
This is achieved by the pin 155. When the breech block is moving
forward to locate the round in the socket 117, the head 156 of
30 the pin 1~5 can enter the cam slot 158 in the firing pin, so
that the pin can retract when its outer end contacts the loading
catch 118. As the breech block completes its forward movement
the underside of the breech block contacts the arms 121 to
depress the loading catch 118, but the-pin 155 plays no part in
35 this. ~owever, when the firing pin is released from the sear
139, the pin head 156 is cammed outwardly by the rounded end of
the cam slot 158, so that by the time the firing pin strikes the
percussion cap 77, the pin 155 is held fuIly extended on the
2 5 ~
-21-
flank of the firing pin. In this position, with the breech
block fully forward, the extended pin 155 contacts a flat upper
forward surface of the catch 118 to hold the catch depressed
so that the limbs 121 can pass under the rim 75 of the round
being extracted and hold down the rim of the next succeeding
live round. ~s t~e firing sequence is completed, the breech
block and firing pin are withdrawn in unison, with the pin 155
hence still extended. This rearward movement first clears the
breech block of contact with the loading catch 118, but the
catch cannot rise again to the position shown in Figure 10 until
the breech block has withdraw~ ~ar enough for the pin 155 to
enter the arcuate portion 123, by which time the spent case has
passed rearwardly clear of the arms 121. It will be seen that
the arr~ngement described has the great advantage of countering
the possi~ility that a round which has not been fired will be
accidentally ejected.
When the spent case is ejected, if there is no further round
present in the magazine, the magazine platform rises under the
influence of the spring 109 until restrained by contact with the
overhanging portion 115. If, however, a further round is present
it is urged upwardly by the spring 109. As it moves upwards, it
is guided forwardly by curved under-surfaces of the limbs 121 of
the loading catch 118, and at its forward end on the chamfered
surface 116. The next round thus moves up in front of the load-
~5 ing catch 118 so that it is held captive by the cheeks 114 andthe overhanging portion 115. A further firing sequence can then
be initiated immediately by operation of the trigger, or alter-
natively the magazine can be re-filled by insertion of one or
more rounds through the opening 112.
:
.
