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BACKGROUND OF THE INVENTION
The pulling of the trigger of firearms of the revolver type to effect
operation of the hammer for accurate firing of the weapon has presented a
problem for many years. This is especially true when preliminary cocking
of the hammer is not resorted to, as in the case of police work. The
relative high pressure or force required to pull or squeeze the trigger
results in the deflection of the weapon off to one side and impairs the
accuracy of the shooting.
Many improved mechanisms for this purpose are found in the prior art. Those
currently known to applicant are set forth below.
Stern, U.S. Pat. No. 845,274 utilizes a helical spring in tension against
the hammer, the latter being pivoted to make this possible. This was
practicable in an old style revolver, circa 1907, when this patent issued.
Lisle, U.S. Pat. No. 970,248 utilizes a helical spring especially adapted
to operate the mechanism for improved utilization of the explosive charge.
Leggett, et al, U.S. Pat. No. 1,007,709 uses a helical spring in
combination with a novel and rather complicated mechanism for improved
action of the hammer relative to the barrel. This is in combination with a
rather complicated trigger mechanism.
Johnson, U.S. Pat. No. 1,004,172 appears to be closest in appearance to
applicant's invention, but is significantly different and does not perform
the function which applicant does as set forth below.
Cobb, U.S. Pat. No. 1,046,268 is merely an improvement on the Johnson
patent cited above.
Johansson, U.S. Pat. No. 1,586,810 is comprised of a helical spring which
performs a routine function and the novely lies in the longitudinal rather
than the pivotal action of the trigger.
Miller, U.S. Pat. No. 3,055,270. This likewise teaches a helical spring in
connection with an automatic revolver having recoiling cylinder frame.
Rohm, U.S. Pat. No. 3,548,530. The spring action here is similar to the
other patents cited where the hammer and trigger are pivotally mounted on
one side of a cover plate.
Baker, U.S. Pat. No. 3,733,730 teaches a rather elaborate mechanism for
providing a constant trigger pull at all positions of the barrel.
Hillberg, et al, U.S. Pat. No. 3,810,326 uses a novel construction of
sub-assemblies of which the spring is a component part.
Baker, U.S. Pat. No. 3,996,686 teaches a construction in which the helical
spring is part of a mechanism in which a gear segment is utilized for
transmissions of the action of the trigger to the hammer.
All of the above prior art entails use of helical springs in various
combinations. The helical springs are almost invariably used in
combination with a concentric plunger sliding within the spring, the whole
assembly being rigidly fixed at each end. No flexibility is provided.
Their action is akin to that of a spring operated poppet valve. In every
case the springs are fixed, at at least one end and sometimes at both
ends.
It is known that the functioning of a helical spring is affected by the
manner in which the ends are constrained, that is whether fixed or hinged.
(See Kent's Mechanical Engineers' Handbook - 12th Edition pp. 11-14 to 11
- 15.)
The effect of lateral or transverse loading of helical springs is also
understood although it is attended by rather complicated mathematical
analysis so that emperical methods are usually employed to get the best
spring action for a given application. (See A. M. Wahl, Mechanical
Springs. Penton Publishing Company, Cleveland 1944.)
I am not aware of any attempts to basically improve the spring action of a
revolver hammer before my improvement disclosed herein.
Some commercial revolvers utilize a leaf spring rather than a helical
spring to provide the spring action necessary for operation of the hammer.
A leaf spring does provide a certain amount of flexibility, overcomes some
of the above disadvantages insofar as uniformity of force required to pull
the trigger is concerned, but is disadvantageous in that it still requires
a relatively hard pull on the trigger to operate the hammer, which pull is
still far from uniform throughout its travel.
SUMMARY OF THE INVENTION
I have invented a mechanism which overcomes all of the above problems. It
combines a helical spring with a link, the assembly being pivoted so that
it could rotate about its opposite ends. This permits a motion of
translation as well as compression of the spring. The results are to
greatly decrease the pressure required to deflect the spring and to make
this pressure uniform throughout the travel of the trigger.
My mechanism is so constructed as to make it readily adapted for
installation in existing revolvers as a substitute for their present
mechanisms, thus greatly improving the operation of these weapons.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side view of a revolver with the handle portion cut away
showing a conventional leaf spring hammer action mechanism.
FIG. 2 is a side view of a revolver with the handle partly cut away showing
my improved helical spring and link hammer action mechanism.
FIG. 3 is an exploded view showing the elements of my improved mechanism.
DESCRIPTION OF A PREFERRED EMBODIMENT
Referring now to the figures and particularly first to FIG. 1, there is
seen the revolver frame 1 and handle 2. The hammer 3 is engaged by lifter
4 which connects with a conventional mechanism to trigger 5. Leaf spring 6
engages hammer 3 through guide pins 7. A recessed area of the back portion
of the hammer is shown at 8 and a slot or groove in the bottom of the
revolver handle for receiving the other end of spring 6 is shown at 9.
Referring now to FIG. 2, there is seen my new mechanism replacing the leaf
spring of FIG. 1. The basic components of the revolver 1 through 9 are the
same with the exception of the leaf spring 6 and pin guides 7. The new
elements or components are shown in the exploded view in FIG. 3 and bear
the same numbers as those of FIG. 2. These are as follows. Helical spring
26 is engaged by plunger 27. The latter has a collar 28 and a ball portion
at one end 29. To adapt my new mechanism to the existing revolver it is
merely necessary to drill a small hole 30 in the recessed portion 8 of the
hammer to receive ball 29.
I next employ angle bracket 31 of partially arcuate configuration having a
bottom end 32 and a hole 33. The hole 33 provides a loose fit for plunger
27. The end 32 abuts in a slot or recess 9 in the frame. In converting
existing leaf spring mechanisms, this may be the slot previously occupied
by the end of the leaf spring 6 as shown on FIG. 1. The slot 9, while
confining bracket 31 to a fixed location in the weapon, permits a certain
amount of angular motion or rotation. The angle bracket 31 thus performs a
double function of acting as a seat for spring 26 and as a link member to
provide a knee action for the entire mechanism. The combined motion of the
ball and the plunger 27, helical spring 26, and angle bracket 31 is such
as to produce the unusual and advantageous effect of reducing the pressure
of pull required on trigger 5 and maintaining the latter uniform
throughout its whole travel.
I have not been able to demonstrate mathematically the performance of this
mechanism by applying principles of analytical mechanics. This appears to
be rather difficult to do, as mentioned above under BACKGROUND OF THE
INVENTION. I have determined however, through empirical tests that the
force required to pull a trigger of a 38 caliber revolver through its
firing cycle is approximately one-half that required with the conventional
hammer and spring mechanism and is uniform throughout the pull. This may
be due to the fact that with my mechanism I get the combined action of
compression of the helical spring with a motion of translation or flexure
of the spring with the added feature of employing pivoted ends for my
spring. The latter is effected by the motion of bracket 31 and ball and
socket 29 and 30 respectively.
In none of the mechanisms for operating the hammer in the prior art cited
is this feature present and since it appears to be an unusual and
unexpected result, it is submitted, that it makes the mechanism as so
claimed patentable over the prior art.
The further advantage of my mechanism as described herein is the ease with
which it may be used to convert and hence improve the operation of
existing revolvers. I have found it expedient to furnish my mechanism in
packaged units with simple instructions to owners of revolvers, utilizing
a leaf spring, who have found it to be extremely advantageous. This has
produced a substantial amount of commercial success.
Although my mechanism was developed specifically for the latter purpose, it
may, of course, be utilized in any revolver as will be evident to those
skilled in the art.
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