US3531886A

US3531886A - Firearm hammer

Info

Publication number: US3531886A
Application number: US732989A
Authority: US
Inventors: Edwin S Vartanian; Jay P Jarvis
Original assignee: Olin Corp
Current assignee: US REPEATING ARMS Co
Priority date: 1968-05-29
Filing date: 1968-05-29
Publication date: 1970-10-06
Anticipated expiration: 1987-10-06

Description

Oct. 6, 1970 E. s. VARTANIAN ETAL 3,531,386

FIREARM HAMMER Filed May 29, 1968 2 Sheets-Sheet 1 INVENTORS EDWIN S. VARTA/V/AN JAY P JARVIS ATTORNEY 0d. 6, 1970 E. YARTANIAN ETAL 3,531,886

' FIREARM HAMMER Filed May 29, 1968 2 Sheets-Sheet 2 l g 4 E ii f Z v j I, v H IrZ/ J INVENTORS saw/1v s. VAR TAN/AN JAY R JARVIS ATTORNEY Patented Oct. 6, 1970 3,531,886 FIREARM HAMMER Edwin S. Vartanian, North Haven, and Jay P. Jarvis,

West North Branford, Conn., assignors t Olin Mathieson Chemical Corporation, a corporation of Virginia Filed May 29, 1968, Ser. No. 732,989 Int. Cl. F41c 11/02, 19/00 US. Cl. 42-69 4 Claims ABSTRACT OF THE DISCLOSURE A two-piece firearm hammer having a tough metal body member and a; hard sear-engaging element connected thereto.

When forming a hammer for use in a firearm, it is desirable to form the body or striking portion of the hammer from a tough steel so as to maximize the resistance of the hammer to shearing forces directed therethrough each time the hammer strikes a firing pin or cartridge. When mounted in a firearm, a portion of the hammer engages a searing member when the hammer is in a cocked position, the searing member serving to releasably latch the hammer in the cocked position. The searing member is operatively connected to a trigger which is operable to disengage the sear from the hammer, thus releasing the latter to strike the firing pin or cartridge. In order to provide for superior operation of the trigger assembly, that portion of the hammer which engages the sear must have a very smooth finish. The smooth finish is required to prevent chattering from occurring between the hammer and the sear as the latter is moved across the sear-engaging portion of the hammer and out of engagement therewith. Chattering between the sear and hammer is undesirable because it makes the shooter consciously aware of the movement of the trigger as the latter is squeezed, and distracts the shooter from focusing his attention on aiming the gun. Not only must the sear-engaging portion of the hammer be originally provided with a very smooth surface, but the surface must also be resistant to nicking and wearing that will occur as a result of repeated contact between the sear and the sear-engaging portion of the hammer. While toughness is a desirable characteristic of a firearm hammer from the standpoint of resisting impact stress, a tough metal will not necessarily provide the needed resistance to nicking and wear which is essential to the sear-engaging portion of the hammer. In order to provide such wear resistance, the sear-engaging portion of the hammer must be comparatively hard. In order to obtain the desired hardness on the sear-engaging portion of the hammer, the latter must be subjected to a heat treatment, which heat treatment undesirably lowers the toughness of the remainder of the hammer. Thus the conventional one-piece hammer of the prior art cannot attain the optimum toughness and hardness without expensive and time-consuming differential heat treatment.

In order to overcome the above problems and to provide a firearm hammer having a body portion of superior toughness, and a sear-engaging portion of superior hardness and smooth finish, a hammer is formed in accordance with this invention having two distinct connected members. The main body is formed from a steel, steel alloy, or other metal which is heat treated to maximize its toughness, and the sear-engaging portion is a distinct member or element formed of a steel, steel alloy, or other metal which is heat treated to maximize its hardness. After heat treating the sear-engaging element is provided with a smooth finish and is attached to the main body of the hammer.

It is, therefore, an object of this invention to provide a firearm hammer having superior trigger pull characteristics.

It is a further object of this invention to provide a firearm hammer formed from a pair of distinct bodies connected together.

It is yet another object of this invention to provide a firearm hammer having a body member of superior toughness, and a sear-engaging member of superior hardness and smooth finish, which sear-engaging member is connected to the body member.

Other features, objects and advantages of this invention will become apparent to one skilled in the art from an examination of the succeeding specification and accompanying drawings, in which:

FIG. 1 is an exploded view of a firearm hammer partially in section formed in accordance with this invention;

FIG. 2 is a perspective view of the assembled hammer of FIG. 1 showing the position of the sear-engaging element on the hammer body:

FIG. 3 is a side view of a cut away portion of a firearm incorporating the hammer of FIG. 2, wherein the hammer is shown in its cocked position in engagement with a scar; and

FIG. 4 is a side view similar to FIG. 3 but showing the hammer in its fired position after disengagement from the sear.

Referring now to FIG. 1, a preferred embodiment of the hammer of this invention is shown. The hammer includes a main body member 2 having a head portion 4 adapted to strike a firing pin or cartridge; and an integral foot portion 6 manually positioned in a firearm adjacent a sear member. A recess 8 is formed in the foot portion 6 and a laterally extending hole 10 is disposed in the member 2 so that the latter may be pivotally mounted in a firearm. The body member 2 is preferably formed from a medium carbon steel, having a carbon content of from about .40.50%, such as 1050 steel or 4140 steel alloy. The hardness of the member 2 is, for example, in the range of 404-5 on the Rockwell C scale, and the toughness of the member 2 as measured by the Izod impact test is, for example, in the range of 20-35 ft. lbs.

The hammer further includes a sear-engaging element in the form of a pin 12 having a barrel portion 14 and a head portion 16. The barrel portion 14 is frictionally fitted into the recess 8 in the hammer foot 6, with the head portion 16 protruding from the hammer foot 6, as is clearly shown in FIG. 2. The head portion 16 in cludes a working surface 18 which engages a sear memher (see FIG. 3). The pin 12 is preferably formed from a high carbon steel, such as, for example, 1095 steel, which has been heat treated to a hardness in the range of, for example, 60*65 on the Rockwell C scale. The working surface 18 has a surface finish of no more than 16 micro inches, with the preferable finish being in the range of 48 micro inches. The finish on the working surface 18 may be economically and efiiciently provided by a centerless grinding operation due to the cylindrical shape of the pin 12. It is noted that the extreme hardness of the pin 12 permits and preserves the smooth finish on the working surface 18. While the head portion 16 is shown as being cylindrical in shape, it is to be understood that the head of the pin can be formed in any of a variety of cross-sections, such as, rectangular, triangular, or the like, without departing from the spirit of the invention. To be operable, the head portion of the pin need merely be capabled of being provided with a smoothly finished working surface.

It is further noted that experimentation has shown that were the hammer body heat treated to a hardness of 60- 65 on the Rockwell C scale, the Izod impact value would decrease to about 6 ft. lb., and thus the toughness of the hammer would be substantially lowered.

FIG. 2 is a perspective view of the hammer of FIG. 1, showing the pin head 16 protruding from the hammer foot 6 so as to expose the working surface 18 for engagement with a sear means.

FIG. 3 shows the hammer 2 mounted in a firearm 20 (only partially shown) for operation with a simple trigger system. The trigger system includes a trigger 22 which is pivotally mounted on a pin 24 and which includes an integral sear means 26. A spring 28 is connected to the sear 26 and the firearm 20 to bias the trigger 22 and sear 26 in a counter-clockwise direction about the pin 24. The hammer 2 is pivotally mounted on a pin 30 and a hammer spring 32 is connected to the pin 30 to bear against the hammer 2 and bias the latter in a clockwise direction about the pin 30. A bolt member 34 is partially shown with a firing pin 36 extending from the rear face thereof, the bolt 34 being shown in its battery position. The hammer 2 is shown in its cocked position in FIG. 3, with the sear 26 engaging the working surface 18 of the protruding head 16 on the sear-engaging element 12.

FIG. 4 shows the hammer 2 after the trigger 22 has been pulled to release the sear 26 from engagement with the sear-engaging element 12. As the trigger 22 is pulled to the left, the trigger system pivots about the pin 24 against the bias of the spring 28 and the right hand edge of the sear 26 slides across the working surface 18 until the sear 26 clears the head 16. At this point, the hammer 2 pivots about the pin 30 under the influence of the hammer spring 32 and the hammer head 4 strikes the firing pin 36.

While the hammer of this invention is shown in operation with a very simple trigger assembly, it is readily apparent that this hammer can be used with trigger assemblies of substantially greater complexity.

It will be readily appreciated by those skilled in the art that this invention provides a firearm hammer having requisite toughness and displaying superior trigger pull characteristics. The hammer of this invention provides for the preservation of the superior trigger pull characteristics even after repeated use, by having a smoothly finished sear-engaging surface of substantially higher hardness than the remainder of the hammer. The provision of a distinct sear-engaging element which is afiixed to the hammer permits formatiton of the former with an accuracy and quality which would be impractical were the hammer formed as a unitary piece in the conventional manner, and further permits a substantially higher hardness to be imparted to the element.

What is claimed is:

1. A hammer for use in a firearm, said hammer comprising a tough metallic member having an impacting portion; a separate metallic sear-engaging element connected to said member, said element having a smoothly finished working surface protruding from said member, said element being of substantially higher hardness than said member.

2. The hammer of claim 1, wherein said member includes a recess, and said sear-engaging element is a pin fitted into said recess.

3. The hammer of claim 1, wherein said working surface has a finish of not more than 16 micro inches.

4. The hammer of claim 1, wherein said member has a hardness of about 4045 on the Rockwell C scale, and said element has a hardness of about 6065 on the Rockwell C scale.

References Cited UNITED STATES PATENTS 10/1913 Smith 42-69 3/1960 Lewis 4265