US3903630A

US3903630A - Firing mechanism for a cartridge firing device

Info

Publication number: US3903630A
Application number: US371264A
Authority: US
Inventors: John T Dirstine
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-06-18
Filing date: 1973-06-18
Publication date: 1975-09-09
Anticipated expiration: 1992-09-09

Abstract

The firing mechanism comprises a hammer and a trigger which are pivotally mounted at spaced points and have relatively approaching portions defining a multipointed cam connection therebetween, the points of which are relatively engageable and disengageable with and from one another when the hammer and trigger undergo rotation with respect to a line through the pivot points thereof. The mechanism also comprises an elongated yieldable biasing means which is interconnected at its ends with the hammer and the trigger on one side of the line. The bias of the biasing means is yieldable intermediate the ends thereof when the points of the cam connection are relatively engaged with one another and a force is applied to one of the hammer and the trigger to rotate the points in the direction relatively away from the line on the other side thereof. However, when a force is applied to the trigger to relatively disengage the points from one another on the other side of the line, the bias is operable firstly, to rotate the hammer into its firing position, and thence, when the latter force is discontinued, to rotate the trigger into the at-rest position thereof.

Description

United States Patent Dirstine FIRING MECHANISM FOR A CARTRIDGE FIRING DEVICE John T. Dirstine, Evergreen State College, Apt. M-302B, Olympia, Wash. 98505 221 Filed: June 18,1973

[2i] Appl. No; 371,264

[76] Inventor:

Primary ExaminerBenjamin A. Borchelt Assistant Examiner-C. T. Jordan Attorney, Agent, or FirmChristensen, OConnor, Garrison & Havelka Sept. 9, 1975 [57] ABSTRACT The firing mechanism comprises a hammer and a trigger which are pivotally mounted at spaced points and have relatively approaching portions defining a multipointed cam connection therebetween, the points of which are relatively engageable and disengageable with and from one another when the hammer and trigger undergo rotation with respect to a line through the pivot points thereof. The mechanism also comprises an elongated yieldable biasing means which is interconnected at its ends with the hammer and the trigger on one side of the line. The bias of the biasing means is yieldable intermediate the ends thereof when the points of the cam connection are relatively engaged with one another and a force is applied to one of the hammer and the trigger to rotate the points in the direction relatively away from the line on the other side thereof. However, when a force is applied to the trigger to relatively disengage the points from one another on the other side of the line, the bias is operable firstly, to rotate the hammer into its firing position, and thence, when the latter force is discontinued, to rotate the trigger into the at-rest position thereof.

4 Claims, 6 Drawing Figures FIRING MECHANISM FOR A CARTRIDGE FIRING DEVICE BACKGROUND FOR THE INVENTION This invention relates to cartridge firing devices, and in particular, to a trigger-actuated firing mechanism for such devices. In prior art mechanisms of this nature, the functions of propelling the hammer against the cartridge and returning the trigger to its at-rest position are performed by two or more springs, both of which are heavily pretensioned. According to the present invention, both functions are performed by a single spring or spring-like biasing means, and the biasing means is incorporated into the mechanism in such a way that it requires very little pretensioning, relative to the prior art. As a result, the trigger can be operated with considerably less pull than was necessary in the devices of the prior art, as well as with a pull which is substantially linear. Both of these features contribute significantly to firing accuracy, since it is well known that the act of tightening the hand, finger and forearm muscles to pull a trigger, can effectively move the gun off target, particularly where the trigger pull must be accentuated to overcome spring resistance in the trigger, and/or requires a non-linear force because of spring reaction in the firing mechanism.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be best understood by reference to the accompanying drawings which illustrate a presently preferred embodiment of the firing mechanism as it is employed in a revolver.

In the drawings,

FIG. 1 is a part-removed, part cross-sectional side elevational view of the revolver showing the firing mechanism in the at-rest condition thereof;

FIG. 2 is another such view of the revolver showing the firing mechanism in the partially cocked condition;

FIG. 3 is a third such view of the revolver showing the firing mechanism in the fully cocked condition of the single action mode of operating the same, or alternatively, in a transitory stage of the double-action mode of operating the same;

FIG. 4 is a fourth such view of the revolver showing the firing mechanism in the firing condition;

FIG. 5 is a fifth such view of the revolver showing the mode by which the firing mechanism reassumes the rest condition from the firing condition of FIG. 4; and

FIG. 6 is a graph illustrating the trigger pull characteristics of the revolver vis a vis those of prior art revolvers.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, it will be seen that the revolver 2 is basically a Model 19 Smith and Wesson Double Action Revolver, and accordingly, is capable of operating either in a single action mode in which the hammer 4 is manually cocked before the trigger 6 is pulled to release the hammer for firing, or in a double action mode in which the hammer is both cocked and released for firing through pull of the trigger alone. In each case, the firing sequence takes place when the hammer is cocked to the condition of FIG. 3, and then released so as to strike one of a plurality of cartridges 8 received in a rotatable cylinder I mounted behind the barrel 12 of the revolver. Moreover, in each case,

the sequence employs a firing mechanism 14 which includes not only the hammer and the trigger, but also a three-pointed cam connection 16 therebetween, the

points

18, 20 and 22 of which are relatively engageable and disengageable with and from one another when the hammer and trigger undergo rotation with respect to a line through the

pivot pins

24 and 26 thereof. As seen, the hammer and the trigger have relatively approaching portions 28 and 30 interposed between the

pins

24 and 26 thereof, and the undersides 32 and 34 of the portions are planar. As the hammer portion 28 approaches the point of maximum convergence with the trigger, it takes the form of a finger 18 which protrudes beyond the forward face 36 of the hammer, adjacent the underside 32 of the portion. Similarly, as the trigger portion 30 approaches the point of maximum convergence with the hammer, it also assumes the form of a finger 20, although in this instance the finger 20 is separated from the underside 34 of the trigger portion by a recess 38 which is deeply inset into the trigger portion 30 and disposed to lie opposite the finger 18 of the hammer in the at-rest condition of the mechanism in FIG. I. The trig ger portion 30 also has a recess or swale 40 in the upper side thereof, which is adapted to enable the trigger portion to be swung into a closer relationship with the cyl inder, as in FIG. 4. The

fingers

18 and 20 constitute two points of the cam connection 16 and operate as a knee joint between the trigger and the hammer in the first stage of the single action mode of the mechanism 14. In the double action mode, however, the finger 20 of the trigger cooperates with a lever 42 which is pivotally connected with the hammer in a position in which it is disposed behind and abreast of the hammer in the drawings. The upper end of the lever is loaded against a stop 44 on the backside of the hammer by means of a spring 46 interposed between the hammer and the lower end 22 of the lever. In the stopped condition, the lower end of the lever is inclined outboard of the forward face 36 of the hammer, and is disposed slightly above the finger 18 of the hammer so as to leave a deeply inset recess 48 therebetween. This recess is adapted to accommodate the finger 20 of the trigger, so that when the mechanism is operated between the condition of FIG. 1 and the condition of FIG. 2, the finger 20 of the trigger bears against the rounded lower end 22 of the lever 42. Of course, the lever in turn bears against the stop 44, so that a turning moment is applied to the hammer. Ultimately, however, the finger 20 escapes from the recess 48 as the mechanism moves from the condition of FIG. 2 to the condition of FIG. 4. On the other hand, when the mechanism moves between the condition of FIG. 5 and the condition of FIG. I, the finger 20 is able to reenter the recess 48 by displacing the lever 42 in the clockwise direction against the bias of the spring 46.

The motions referred to above are effected in part against, and in part with the aid of a coiled spring 50 caged between the hammer and the trigger. As seen,

other portions

52 and 54 of the hammer and the trigger depend from the same at the remote ends of the planar undersides 32 and 34 of the members, and these portions are mutually opposed to one another when the mechanism is in the condition of FIG. I. The depending portion 54 of the trigger has a cup-shaped recess 56 therein, whereas the depending portion 52 of the hammer has an oblique-angled slot 58 therethrough. The spring 50 is caged about a rod 60, one end of which has a flanged cap 62 thereon which is accommodated in the recess 56 of the trigger portion 54. The other end 60' of the rod is inserted in the slot 58 and has a washer 64 slidably engaged thereon which is trapped between the spring and the depending portion 52 of the hammer to serve as a compression flange for the spring.

In the at-rest condition of FIG. 1, the fingers l8 and 20 of the relatively approaching portions 28 and 30 of the hammer and the trigger are disposed below the line between the

pivot points

24 and 26 of the members, and the hammer and the trigger are biased by the spring 50 in the clockwise and counterclockwise directions, respectively, there being a stop 66 for the trigger below the cylinder, and a stop (not shown) for the hammer at the rear end of the cylinder. When a counterdirectional force is applied to either the hammer or the trigger, the finger 20 is either engaged with the end 22 of the lever 42, or is engaged by the finger 18, thus dictating that the members will rotate together, but counterdirectionally, toward the line between the

points

24 and 26. Moreover, the spring 50 is compressed between the depending

portions

52 and 54 of the hammer and the trigger, as seen in FIG. 2. Ultimately, the fingers l8 and 20 move to the upper side of the line, and in the single action mode of the mechanism, the hammer assumes a cocked condition, and remains in this condition until it is disturbed by the application of a new force to the trigger. See FIG. 3. When such a force is applied, or when a trigger force is applied and continued as in the case of the double action mode of operation, then the finger 20 is driven in the clockwise direction out of the recess 48 so as to escape the connection 16 entirely. At the same time, the hammer is released to operate against a cartridge 8 under the bias of the spring 50. See FIG. 4. Subsequently, when the trigger force is discontinued, the energy remaining in the spring 50 is employed to return the trigger to its at-rest condition of FIG. 1, and as explained earlier, the trigger finger 20 reenters the recess 48 by depressing the lever 42 against the spring 46. See FIG. 5.

During the latter operation, moreover, a pawl 68 operates to rotate the cylinder in conventional fashion.

In summary then, the spring 50 provides the necessary energy for all phases of the firing operation, including firing and trigger return. Moreover, due to the nature and disposition of the spring, the pull which must be exerted on the trigger is considerably less than was necessary with the multiple spring assemblies employed in the prior art. Also, because of the nature and disposition of the spring, the pull is substantially linear.

The pull is contrasted with the prior art in FIG. 6. The dashed line represents the trigger pull necessary for a conventional firing mechanism; the solid line represents that necessary for the mechanism of the present invention. With the conventional mechanism, it will be noted that the initial pull necessary to overcome the static resistance of the hammer spring at T, is often as high as twelve pounds, and that after the initial pull, a nonlinear pull of as high as sixteen pounds is necessary to achieve firing at T On the other hand, in the case of the present invention, the initial pull necessary to overcome the static resistance of the coil spring 50, is normally only a maximum of two pounds at T and thereafter firing is effected at T with a substantially linear pull of no more than seven pounds.

1 claim:

1. in a cartridge firing device, a firing mechanism comprising a hammer and a trigger pivotally mounted at spaced points and having portions thereof which relatively approach one another and define a multipointed cam connection therebetween, the points of which cam connection are relatively engageable and disengageable with and from one another when the hammer and the trigger undergo rotation with respect to a line through the pivot points thereof, and also having portions thereof which in general are mutually opposed to one another on one side of the line when the hammer and trigger are in the firing and at-rest positions thereof, respectively, an elongated rod, the respective end portions of which are pivotally connected with the mutually opposing portions of the hammer and the trigger at points spaced apart from the line through the pivot points of the hammer and the trigger, said rod being telescopic relative to the mutually opposing portions of the hammer and the trigger, and a coiled spring which is caged by the rod between the mutually opposing portions of the hammer and the trigger, so as to yield intermediate the ends of the rod when the points of the cam connection are relatively engaged with one another and a force is applied to one of the hammer and the trigger to rotate the points of the cam connection in the direction relatively away from the line on the other side thereof, and so as to rotate the hammer into its firing position when a force is applied to the trigger to relatively disengage the points of the cam connection from one another on the other side of the line, and then to rotate the trigger into the at-rest position thereof when the latter force is discontinued.

2. The cartridge firing device according to claim 1 wherein the points of the cam connection relatively engage one another on the one side of the line when the hammer and the trigger are in the firing and atrest positions thereof, respectively.

3. The cartridge firing device according to claim 1 wherein the one mutually opposing portion has an oblique angled slot therethrough, and the one end portion of the rod is inserted in the slot and slidably engaged with the one mutually opposing portion at the mouth of the slot, there being a washer-like element slidably engaged on the rod between the spring and the one mutually opposing portion at the mouth of the slot.

4. The cartridge firing device according to claim 3 wherein the other mutually opposing portion has a cup shaped recess therein, and the other end portion of the rod has a flanged cap thereon which is pivotally engaged in the recess, with the spring bearing against the flange thereof.

i It i i

Claims

1. In a cartridge firing device, a firing mechanism comprising a hammer and a trigger pivotally mounted at spaced points and having portions thereof which relatively approach one another and define a multi-pointed cam connection therebetween, the points of which cam connection are relatively engageable and disengageable with and from one another when the hammer and the trigger undergo rotation with respect to a line through the pivot points thereof, and also having portions thereof which in general are mutually opposed to one another on one side of the line when the hammer and trigger are in the firing and at-rest positions thereof, respectively, an elongated rod, the respective end portions of which are pivotally connected with the mutually opposing portions of the hammer and the trigger at points spaced apart from the line through the pivot points of the hammer and the trigger, said rod being telescopic relative to the mutually opposing portions of the hammer and the trigger, and a coiled spring which is caged by the rod between the mutually opposing portions of the hammer and the trigger, so as to yield intermediate the ends of the rod when the points of the cam connection are relatively engaged with one another and a force is applied to one of the hammer and the trigger to rotate the points of the cam connection in the direction relatively away from the line on the other side thereof, and so as to rotate the hammer into its firing position when a force is applied to the trigger to relatively disengage the points of the cam connection from one another on the other side of the line, and then to rotate the trigger into the at-rest position thereof when the latter force is discontinued.