Firearms – Electric appliances
Reexamination Certificate
2001-12-20
2003-06-03
Carone, Michael J. (Department: 3641)
Firearms
Electric appliances
C042S069030, C042S065000
Reexamination Certificate
active
06571502
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to firearms. More specifically, the present invention relates to electronically fired revolvers in which a latch mechanism is incorporated to release the hammer at a desired point in trigger motion after the cylinder has carried up.
BACKGROUND OF THE INVENTION
Revolvers have been produced for over a century and, although continuous efforts have led to improvements in safety, manufacturing, and operation of revolvers, many components in their firing mechanism have remained relatively unchanged in function and design. Notably, the mechanical linkage between trigger, hammer and cylinder, i.e., the firing mechanism, still utilizes a basic design that requires direct engagement between the trigger and hammer in order to cock and fire the revolver.
In a conventional revolver a relatively large amount of force must be exerted on the trigger and main spring in order to load the hammer with enough potential energy to reliably discharge the cartridge. The relatively large force causes inherent problems in accurately aiming the firearm. This is especially problematic in double action (DA) revolvers, where the cylinder must be fully rotated, and the hammer must be cocked and fired in a single motion of the trigger.
Additionally, in double action revolvers, it is often difficult for an operator to discern the letoff point in the trigger movement, i.e., the point at which the movement of the trigger fully cocks the hammer and further trigger movement will release the hammer for firing. Moreover, the letoff point in a conventional firing mechanism varies greatly with tolerances and wear of the various mating surfaces involved in the linkage of the firing mechanism.
More recently, electronics have been incorporated into firearms to further improve the cost, manufacturability, and performance of the firearms. One such example of an electronic revolver is disclosed in the above referenced U.S. patent application Ser. No. 09/616,722 (′722).
Referring to
FIGS. 1 and 2
, an embodiment of a revolver in accordance with the ′722 application is shown generally at
10
. The ′722 application describes a revolver
10
having an electronic firing apparatus adapted to produce a firing signal. The revolver
10
includes a frame
12
, a cylinder
14
having a firing chamber to receive a cartridge therein. The revolver also includes a barrel with a firing axis attached to the frame in alignment with the firing chamber and a trigger
16
. A linearly displaceable firing probe
18
(as opposed to a conventional firing pin) is disposed within the frame
12
for linear reciprocal movement from a probe recovered position, wherein the firing probe
18
is retracted away from the cartridge, to a probe contacting position, wherein the firing probe
18
is disposed forwardly in contact with the cartridge (not shown). Actuation of the trigger
16
causes the firing probe
18
to move from the probe recovered position to the probe contacting position only when an electronic security apparatus (not shown) determines the revolver
10
is in a firing mode and the operator is an authorized operator.
An embodiment of a firing mechanism in accordance with the ′722 application is shown generally at
20
. The firing mechanism
20
includes the trigger
16
, a hammer
22
, a sear
24
, a transfer bar
25
, a hand
26
, a rebound
28
, a main spring (or rebound spring)
30
, a stirrup
32
, and a link
34
. A trigger lever
36
is coupled between the trigger
16
and the rebound
28
to compress the main spring
30
.
The hand (or ratchet arm)
26
is connected to the trigger
16
via hand pin
27
, and has a configuration and function known well in the industry to index the cylinder
14
as the trigger
16
is pulled. During actuation of the firing mechanism
20
, it is important that the hand
26
fully index and align the cylinder
14
with the firing axis of the revolver
10
just before the trigger
16
reaches the letoff point and releases the hammer
22
for firing. For purposes of this application this indexing and alignment is defined as the “carry-up” of the cylinder. In this regards, the tolerences of the hand pin
27
and the length of the hand
26
are critical for achieving carry-up.
Movement of the entire firing mechanism
20
is governed predominantly by three pivot pins which mount and secure the firing mechanism
20
in a cavity
31
of the frame
12
. The stirrup
32
is pivotally mounted by a stirrup pin
38
, the hammer
22
is pivotally mounted by a hammer pin
42
, and the trigger is pivotally mounted by a trigger pin
40
. The frame
12
has a contoured cam surface
44
located and shaped within the cavity
31
to guide the transfer bar
25
during early stages of firing mechanism
20
actuation described below.
The trigger
16
includes a trigger post
46
with a flat upper surface
48
which bears generally vertically against the distal end of the sear
24
during early stages of firing mechanism
20
actuation. The trigger post
46
defines a trigger pocket
50
that receives the transfer bar
25
throughout the entire cycle of firing mechanism
20
actuation. The lower end of the trigger pocket
50
forms a relatively sharp let-off apex
52
designed to engage a foot
54
of the hammer
22
during the later stages of firing mechanism
20
actuation.
FIG. 1
shows the firing mechanism
20
in its “recovered position”, i.e., the normal rest position that the components of the firing mechanism
20
return (or recover) to when the revolver
10
is fired and the trigger
16
is released.
FIG. 2
shows the relative position of the various components of the firing mechanism
20
at its let-off point, i.e., the point at which the hammer
22
is fully cocked. and further trigger
16
movement will release the hammer
22
from the trigger
16
for firing.
Problematically, as illustrated in
FIG. 2
, minor deviations in the trigger to hammer linkage will greatly affect the letoff point. That is, small tolerance or wear variations in the surfaces at the trigger's letoff apex
52
and the hammer's foot
54
can result in large angular deviations
56
in trigger position at the letoff point. Moreover, the tolerances and wear of the trigger pin
40
and hammer pin
42
also significantly contribute to the angular deviation
56
.
Just as critically, the tolerances of the angular deviation
56
also affect the carry-up of the cylinder, i.e., indexing and alignment of the cylinder chamber with the firing axis, which must be accomplished just before the letoff point. This is because the hammer and hand are both directly engaged with the trigger. As a result, the carry-up is affected by both the trigger to hammer linkage as well as the trigger to hand linkage. That is, in addition to the angular deviation
56
caused from tolerances of the trigger to hammer linkage, the tolerances of the length of the hand
26
as well as the tolerances in the hand pin
27
, i.e., the trigger to hand linkage, further exacerbate the problem of accurately achieving carryup. Moreover, because the hammer
22
and hand
26
are each directly linked to the trigger,
16
, there is no way to separate the constraints of the trigger to hammer linkage from the trigger to hand linkage, therefore making manufacturing more difficult.
Based on the foregoing, it is the general object of the present invention to provide an electronically fired revolver that overcomes the problems and drawbacks associated with prior art revolvers.
SUMMARY OF THE INVENTION
The present invention offers advantages and alternatives over the prior art by providing a revolver having a latch mechanism between the hammer and trigger, such that the hammer does not directly engaged with the trigger during actuation of the firing mechanism. Accordingly, the linkage between the hammer and latch is separate from the linkage between the trigger and hand. As a result, the tolerance build up in each linkage can be treated as two parallel designs rather than being stacked in series upon one another, the
Carone Michael J.
Chambers Troy
McCormick Paulding & Huber LLP
Smith & Wesson Corp.
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