Patent Description:
The retention/arming of a hammer in a traditional hammer-fired firing mechanism for a firearm is done by a surface on the hammer that interacts with a corresponding surface on a sear. This interface is typically protected from unintentional disconnection by using a balanced sear, a spring to bias the sear's position in relation to the hammer, and/or an interface geometry that produces a positive engagement between the hammer and sear surfaces.

One major shortcoming of such an interface is that the hammer will not be retained in the event the interface is physically damaged and fails to keep the two parts engaged. Another issue resulting from an interface failure is that, particularly in auto-loading weapons, the hammer can "follow" a slide or operating group after being reset and fire additional rounds without the user further manipulating the trigger, essentially rendering the firearm in fully automatic mode until the magazine is empty. While external safeties can be added to reduce the risk of a discharge in case the hammer-sear interface fails, such external safeties are not automatically activated and must be manually set. Document <CIT> discloses a trigger group comprising a trigger and a hammer wherein the hammer comprises a cam surface.

The invention is a firing mechanism according to claims <NUM> or <NUM>, and their dependent claims.

Embodiments of the present disclosure address the above problems and more by providing a secondary interface between the hammer and sear of a firearm that will automatically be engaged in case the primary interface fails. In various embodiments, the secondary safety interface is part of the hammer and sear and does not require any additional components.

According to embodiments of the present disclosure, in the event of a primary interface failure, the secondary safety interface will engage without any further action and will hold the hammer in its "armed" position. Further, embodiments of the secondary interface, when activated, disconnect the hammer and the sear from the trigger, creating a locked-out condition. Manually cycling the slide or operating group of the weapon will not allow the secondary interface to be separated and the secondary interface will re-engage every time until the weapon is disassembled for repair. The locked-out mechanism, among other things, allows for a safe disassembly of the weapon. As such, the presently disclosed firing mechanism with secondary interface provides significant safety against unintentional discharge of the firearm in case of part failures.

The presently disclosed subject matter now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the presently disclosed subject matter are shown. The presently disclosed subject matter may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Indeed, many modifications and other embodiments of the presently disclosed subject matter set forth herein will come to mind to one skilled in the art to which the presently disclosed subject matter pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the presently disclosed subject matter is not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims.

It will be appreciated that reference to "a", "an" or other indefinite article in the present disclosure encompasses one or more than one of the described element. Thus, for example, reference to a spring encompasses one or more springs, reference to a round encompasses one or more rounds, and so forth.

As shown in <FIG>, a firing mechanism <NUM> according to embodiments of the present disclosure includes a trigger group frame or housing <NUM>, a trigger <NUM>, a trigger bar <NUM>, a hammer <NUM>, a sear <NUM> and an actuator <NUM>. It will be appreciated that embodiments of the firing mechanism <NUM> can involve a subset of these elements, such as the hammer <NUM>, sear <NUM> and actuator <NUM>, for example.

As shown in <FIG> and other figures, the hammer <NUM> is formed with a body <NUM> and opposed legs 42A and 42B, each of which includes a respective opening 43A, 43B for receiving a hammer spring <NUM> and a hammer pin <NUM>. Leg 42B can be formed as a rim of constant thickness or depth D1 that forms the opening 43B, whereas leg 42A can be formed as a rim having a wider depth D2 for approximately three quarters of the rim and a narrower depth (not shown) for approximately one quarter of the rim. Leg 42A is thus formed with an internal wall <NUM> on the narrower depth portion extending between a leading edge <NUM> and a trailing edge <NUM> of the wider depth portion D2. In this way, the hammer <NUM> provides a cavity <NUM> in which a portion of the sear <NUM> to resides during operation as described herein. A hammer head segment <NUM> is formed with the body <NUM> and extends away from the opposed legs 42A and 42B. The hammer head segment <NUM> includes a striking face <NUM> which impacts a firing pin (not shown) during operation of the firearm. The hammer head segment <NUM> is further formed with a rampart wall <NUM> extending downwardly from the striking face <NUM> and a latching edge <NUM> extending laterally inwardly toward the legs 42A and 42B from the rampart wall <NUM>. A sear facing wall <NUM> extends from the latching edge <NUM> and lies opposite a hammer slot wall <NUM>, wherein the sear facing wall <NUM> and the hammer slot wall <NUM> form an opening <NUM> for receiving a sear extension arm <NUM> of the sear <NUM> during operation.

As shown in <FIG> and other figures, the sear <NUM> is formed with a body <NUM> having a bored opening <NUM> and an extension base <NUM> formed with a foot <NUM> having an opening <NUM> opposed to opening <NUM>, wherein a sear spring <NUM> can be positioned between the body <NUM> and extension base <NUM> and a sear pin <NUM> can be inserted through the openings <NUM>, <NUM> and the sear spring <NUM>. The sear <NUM> is formed with an extension arm <NUM> extending substantially perpendicularly above the bored opening <NUM> and proximate a first end <NUM> of the body <NUM>. The extension arm <NUM> is formed with a first hook <NUM> having a top jaw surface <NUM>, which slidingly engages the latching edge <NUM> of the hammer <NUM> during operation of the firing mechanism as described elsewhere herein. The sear <NUM> is further formed with a second hook <NUM> proximate a second end <NUM> of the body <NUM>, wherein the second hook <NUM> can be provided with a generally C-shaped cross-section and an actuator-engaging head <NUM>. The inner surface <NUM> of the second hook <NUM> forms a slot <NUM> wherein portions of an actuator arm <NUM> of the actuator <NUM> may reside during different operations of the firing mechanism of the present disclosure. The outer surface <NUM> of the second hook <NUM> can engage trailing edge <NUM> of the inner portion of the hammer <NUM> during operation, as described elsewhere herein. This engagement between outer surface <NUM> of the second hook <NUM> and the trailing edge <NUM> of the hammer <NUM> provides a secondary interface <NUM> in accordance with embodiments of the present disclosure.

As shown in <FIG> and other figures, the actuator <NUM> is formed with an actuator base <NUM> and an actuator arm <NUM> extending radially outwardly of the actuator base <NUM>, wherein the actuator base <NUM> includes an actuator bore <NUM> extending axially therethrough. The actuator base <NUM> can be formed with a spring slot <NUM> and the actuator arm <NUM> can be formed with a pair of opposed prongs <NUM>, <NUM> forming a notch <NUM> therebetween. The actuator arm <NUM> can further be formed with an extension rod <NUM> extending substantially perpendicularly therefrom, and an actuator interface <NUM> extends radially outwardly from the extension rod <NUM>. The spring slot <NUM> is sized to receive an actuator spring <NUM>, and an actuator pin <NUM> extends through the actuator bore <NUM> and through the actuator spring <NUM>. In various embodiments, the actuator interface <NUM> extends from the actuator arm <NUM> for manually blocking the actuator <NUM> from separating from the sear <NUM>. This is illustrated in <FIG>, where a safety lever <NUM> engages actuator interface <NUM> at edge <NUM>. As the safety lever <NUM> is secured about and engaged with sear pin <NUM>, any restriction on the rotation of the safety lever <NUM> will restrict the rotation of the sear <NUM>.

The frame or housing <NUM> is provided with opposing hammer pin openings <NUM><NUM>, sear pin openings <NUM> and actuator pin openings <NUM> for receiving the hammer pin <NUM>, sear pin <NUM> and actuator pin <NUM>, respectively. This enables the hammer <NUM> to be pivotably mounted about a hammer pin axis A, sear <NUM> to be pivotably mounted about a sear pin axis B and actuator base <NUM> to be pivotably mounted about an actuator axis C. When installed in the frame or housing <NUM>, the hammer spring <NUM> biases the hammer <NUM> against the frame or housing <NUM> so that the hammer <NUM> is inclined to rotate clockwise with sufficient force to carry out its duty to forcibly strike a firing pin when the trigger <NUM> is pulled. When installed in the frame or housing <NUM>, the sear spring <NUM> biases the sear <NUM> against the frame or housing <NUM> so that the sear <NUM> is inclined to rotate counterclockwise. A primary interface <NUM> is operably formed between the top jaw surface <NUM> of the first hook <NUM> of the sear <NUM> and the latching edge <NUM> of the hammer head segment <NUM> of the hammer <NUM>. The sear spring <NUM> biases the first hook <NUM> into the primary interface <NUM> and biases the second hook <NUM> towards the hammer <NUM>. The hammer spring <NUM> biases the hammer <NUM> into the primary interface <NUM> and is operable to overcome the biasing of the sear spring <NUM>. Additionally, when installed in the frame or housing <NUM>, the actuator spring <NUM> biases the actuator <NUM> against the frame or housing <NUM> so that the actuator <NUM> is inclined to rotate clockwise. In various embodiments, the actuator <NUM> is prevented from rotating due to the actuator-engaging head <NUM> of the second hook <NUM> of the sear <NUM> being positioned in the notch <NUM> between the prongs <NUM>, <NUM> of the actuator arm <NUM>, as shown in <FIG>, for example.

During ordinary operation with all parts intact, when a user pulls trigger <NUM>, the trigger bar <NUM> pushes the extension rod <NUM> of the actuator <NUM>, causing the actuator to rotate about axis C against its bias in a counterclockwise direction. Such rotation causes the actuator-engaging head <NUM> of the second hook to slide past prong <NUM> and then the spring force of the hammer spring <NUM> overcomes the resistance from the sear spring <NUM> such that the top jaw surface <NUM> of the first hook <NUM> of the sear <NUM> slides down the latching edge <NUM> and thereby releases the hammer <NUM> so that the hammer <NUM> can strike the firing pin. The trigger <NUM> is thus operable to rotate the actuator <NUM> about the actuator axis C (represented by actuator pin <NUM> location in <FIG>) to disengage the second hook <NUM> of the sear <NUM> from the notch <NUM> of the actuator arm <NUM>, thereby permitting the first hook <NUM> of the sear <NUM> to release the hammer <NUM> and permit the firearm to be discharged. At this time, both prongs <NUM>, <NUM> of the actuator <NUM> are positioned in the slot <NUM> of the second hook <NUM> of the sear <NUM>.

Subsequent to firing the firearm, the slide (not shown) is racked to reset the hammer, whereupon the slide engages the hammer body <NUM> and overcomes the biasing force of the hammer spring <NUM> to re-engage the top jaw surface <NUM> of the first hook <NUM> of the sear with the latching edge <NUM> of the hammer head segment <NUM> of the hammer <NUM>. As the sear rotates counterclockwise about its axis while the slide is re-racked, the second hook <NUM> is lifted away from the actuator prongs <NUM>, <NUM>, allowing the actuator <NUM> to rotate clockwise about its axis so that the prongs <NUM>, <NUM> align around the actuator-engaging head <NUM>. As the re-racking process is complete and the slide finishes engagement with the hammer <NUM>, the hammer rotates slightly back in the clockwise direction, whereupon the actuator-engaging head <NUM> rotates to a position within the notch <NUM> between prongs <NUM>, <NUM>. <FIG> illustrates the position where the top jaw surface <NUM> of the hammer <NUM> is not engaged with the latching edge <NUM> of the sear <NUM>, and <FIG> illustrates the position where the top jaw surface <NUM> of the hammer <NUM> is engaged with the latching edge <NUM> of the sear <NUM>, thereby providing the primary interface <NUM>. It will be appreciated that the hammer spring <NUM> pulls the hammer <NUM> upwards which causes a force on the sear <NUM> to push into the actuator <NUM>. While the sear spring <NUM> acts to push the sear <NUM> upwards, this force is overcome by the load applied through the primary interface <NUM>. The result is that the sear <NUM> is pushed down on the actuator <NUM>. In <FIG>, the secondary interface <NUM> is indicated at the point of contact of the outer surface <NUM> of the second hook <NUM> and the trailing edge <NUM> of the hammer <NUM>.

In the instance of a failure of the primary interface <NUM> as illustrated in <FIG>, for example, where the first hook <NUM> has broken off, there is no surface such as top jaw surface <NUM> (shown in <FIG>) to engage the latching edge <NUM> of the hammer <NUM>. In such instance, the hammer <NUM> is no longer retained by the sear <NUM> and the hammer will rotate clockwise (towards a firing pin) until the secondary interface <NUM> engages. The sear spring <NUM> pushes the sear <NUM> upward to help maintain the interaction on the secondary interface <NUM>. The sear <NUM> may still rest on the actuator <NUM>, or slightly lift off the contact surface as shown in <FIG>. At this stage, the secondary interface <NUM> between the hammer <NUM> and the sear <NUM> will not be separated unless the firing mechanism <NUM> is removed from the firearm.

Once the primary interface <NUM> has failed and the secondary interface <NUM> has engaged, an outside action applied to the fire control such as a user pulling the trigger <NUM> will not result in the hammer <NUM> releasing towards the firing pin. On the other hand, the sear <NUM> may be pushed farther into engagement with the hammer <NUM> at the secondary interface <NUM>. Further, an outside action such as a user racking the slide to reset the hammer <NUM> will result in the hammer <NUM> being rotated to its lowest position, relieving the pressure on the interface <NUM>. The sear spring <NUM> rotates the sear <NUM> to its most upward position before the hammer <NUM> is released under the slide and applies pressure again. At this point, any interaction with the actuator <NUM> is impossible and the shooter will experience a "dead trigger". It will thus be appreciated that the failure of the first hook <NUM> and/or first interface <NUM> renders the trigger <NUM> inoperable for discharging the firearm. The secondary interface <NUM> thus prevents an accidental discharge of the firearm in case of failure of a part such as the sear <NUM> and further locks the firing mechanism in a condition where the user cannot fire another round but can safely unload and disassemble the firearm for troubleshooting.

It will be appreciated that the primary interface <NUM> and the secondary interface <NUM> are at different distances from the sear axis B. As shown in <FIG>, the secondary interface <NUM> is farther than the primary interface <NUM> from the sear axis B (represented by sear pin <NUM> location) to ensure it will disengage first and will not inhibit the normal operation of the firing mechanism. Further, the alignment of the interfaces <NUM>, <NUM> on the hammer are opposite. As shown in <FIG>, the primary interface <NUM> is farther away from the hammer axis A (represented by hammer pin <NUM> location) than the secondary interface <NUM> to allow the hammer spring <NUM> to create a larger force on the sear <NUM> and force the disconnect once the actuator <NUM> is moved out of the way.

Claim 1:
A firing mechanism (<NUM>), comprising:
a hammer (<NUM>) pivotably mounted about a hammer axis (<NUM>);
a sear (<NUM>) pivotably mounted about a sear axis (<NUM>), wherein the sear (<NUM>) comprises a first hook (<NUM>) operable to provide a primary interface (<NUM>) with the hammer (<NUM>);
an actuator (<NUM>) comprising an actuator base (<NUM>) and an actuator arm (<NUM>) extending radially outwardly from the actuator base (<NUM>), wherein the actuator base (<NUM>) is pivotably mounted about an actuator axis (<NUM>); and
wherein the sear (<NUM>) further comprises a second hook (<NUM>) operable to provide a secondary interface (<NUM>) with the hammer (<NUM>) and wherein, upon failure of the first hook (<NUM>), the second hook (<NUM>) secures the hammer (<NUM>) and prevents discharge of the firearm characterized in that
the actuator arm (<NUM>) comprises a notch (<NUM>) and further comprising a trigger (<NUM>) operable to rotate the actuator (<NUM>) about the actuator axis (<NUM>) to disengage the second hook (<NUM>) of the sear (<NUM>) from the notch (<NUM>) of the actuator arm (<NUM>), thereby permitting the first hook (<NUM>) of the sear (<NUM>) to release the hammer (<NUM>) and permit the firearm to be discharged.