Patent Description:
<CIT> discloses a firearm hammer blocking safety mechanism.

Hammer-operated firearms such as revolvers in one form typically include a cylinder frame which rotatably supports a revolving cylinder having a plurality of chambers for holding cartridges and a grip frame that provides a structure for mounting and supporting a hand grip attached thereto at the rear of the revolver. The barrel of the revolver is also mounted to the front of or forms part of the cylinder frame.

Rotating hammers as used in revolver and many other types of firearms to transfer stored energy into a firing pin and ignite a primer in a cartridge. In many configurations, the hammer is held in a rearward cocked position by a trigger mechanism, and released when the trigger is pulled or moved by the shooter. It is undesirable to have the hammer release when the firearm is dropped or impacted, and there are numerous methods and mechanisms used to prevent firearms from firing during these situations. Some firearms are more sensitive to releasing the hammer when impacted in particular directions or dropped in particular orientations.

Accordingly, an improved safety mechanism for a revolver is desired.

A firearm according to the present disclosure includes a safety mechanism configured and operable to address the foregoing firearm drop and impact situations. The firearm may be a revolver herein in one non-limiting embodiment for illustrative purposes of the safety mechanism; however, the safety mechanism is broadly adaptable to many other types of hammer-operated firearms including for example without limitation pistols, rifles, and shotguns. The term firearm as used herein therefore should be broadly construed.

The firearm includes a housing which may be a cylinder frame in one embodiment which carriers a rotatable cylinder. A rotatable hammer is mounted about a transverse pivot pin in the housing at the rear of the cylinder. In general, the safety mechanism in one embodiment comprises a biased blocking member such as a cylindrical blocking pin in one non-limiting embodiment mounted within a recess or bore in the hammer. The blocking pin is selectively engageable with a blocking feature on the hammer pivot pin, which may be a blocking notch in one non-limiting embodiment. The hammer pivot pin may be non-rotating relative to the housing in one implementation. When exposed to an abnormal force such as via dropping the firearm when the hammer is in a cocked position, the blocking pin moves into the blocking notch formed in the non-rotating hammer pivot pin to stop or delay the motion of the hammer. The hammer blocking pin thus operably interacts directly with the non-rotating hammer pivot pin. Advantageously, the hammer blocking safety mechanism is automatically deployed without manual operation or intervention by the user.

According to one aspect, a firearm with safety mechanism comprises: a housing; a spring-biased hammer rotatably supported by a transverse hammer pivot pin fixed in position relative to the housing, the hammer movable between a rearward cocked position and a forward firing position; a trigger operable to release the hammer from the cocked position to discharge the firearm; a blocking feature formed on the hammer pivot pin; and a hammer blocking member movably mounted to the hammer and selectively engageable with the blocking feature; wherein rotating the hammer from the firing position to the cocked position aligns the blocking member with the blocking feature of the hammer pivot pin such that the blocking member is movable to engage the blocking feature. In one embodiment, the blocking feature is a notch and the blocking member is a cylindrical pin.

According to another aspect, a revolver with safety mechanism comprises: a cylinder frame supporting a rotatable cylinder defining a plurality of cartridge-receiving chambers; a spring-biased hammer rotatably supported by a stationary hammer pivot pin arranged in the frame, the hammer movable between a rearward cocked position and a forward firing position; a trigger engageable with the hammer and operable to release the hammer therefrom; a blocking notch formed on the hammer pivot pin; and a hammer blocking pin movably mounted to the hammer and selectively engageable with the blocking feature; wherein rotating the hammer from the firing position to the cocked position aligns the blocking pin with the blocking notch of the hammer pivot pin such that the blocking pin is slideably engageable with the blocking notch.

In another aspect, a method for blocking a firing mechanism of a firearm comprises: providing the firearm including a hammer mounted about a hammer pivot pin and rotatable between a rearward cocked position and a forward firing position, a trigger operable to release the hammer, and a movable blocking member; positioning the hammer in the firing position, the blocking member being misaligned with a blocking feature on the hammer pivot pin; rotating the hammer to the cocked position; aligning the blocking member with the blocking feature on the hammer pivot pin; impacting the firearm on a surface; automatically moving the blocking member from a retracted position disengaged from the blocking feature of the hammer pivot pin to a projected position engaged with the blocking feature; and arresting rotation of the hammer to prevent discharging the firearm via the blocking member engagement with the blocking feature.

The features of the exemplary embodiments will be described with reference to the following drawings where like elements are labeled similarly, and in which:.

All figures are schematic and not necessary to scale. Features numbered in some figures but not in others are the same features unless expressly noted otherwise.

The features and benefits of the invention are illustrated and described herein by reference to exemplary ("example") embodiments. In the description of embodiments disclosed herein, any reference to direction or orientation is merely intended for convenience of description and is not intended in any way to limit the scope of the present invention. Relative terms such as "lower," "upper," "horizontal," "vertical,", "above," "below," "up," "down," "top" and "bottom" as well as derivative thereof (e.g., "horizontally," "downwardly," "upwardly," etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the apparatus be constructed or operated in a particular orientation. Terms such as "attached," "affixed," "connected" and "interconnected," refer to a relationship wherein structures are secured or attached to one another either directly or indirectly through intervening structures, as well as both movable or rigid attachments or relationships, unless expressly described otherwise. Moreover, the features and benefits of the invention are illustrated by reference to the exemplary embodiments.

<FIG> depict a firearm in the form of a revolver <NUM> and components thereof including a hammer-blocking safety mechanism according to the present disclosure. The revolver may be a double-action revolver in one embodiment; however, the revolver in other embodiments may be a single action revolver. Either design may be used and is not limiting of the present invention. In other embodiments, the firearm may be a pistol with fixed receiver or a reciprocating receiver (i.e. slide), or a long gun such as a rifle or shotgun.

Revolver <NUM> includes a barrel <NUM> supported by a housing <NUM>. Depending on the type firearm, the housing may be any of the following including but not limited to a frame or chassis of any type firearm, a cylinder frame of a revolver, a fixed receiver of a pistol, rifle, or shotgun, a reciprocating receiver of a pistol (aka "slide"), a trigger or firing control housing which supports at least some firing components of the firing mechanism and is attachable to a frame or chassis, or any other type of housing used in a firearm. The term "housing" therefore should be broadly construed in a non-limiting manner to encompass any of the foregoing examples.

The housing <NUM> of the present revolver <NUM>, which may alternatively be referred to as a cylinder frame or alternatively receiver in the art, rotatably carries a cylinder <NUM> defining a plurality of chambers <NUM> formed inside therein for holding ammunition cartridges. In various embodiments, housing <NUM> preferably be may be made of metal (e.g. aluminum, titanium, steel, etc.), suitable strong plastic, or combinations thereof.

Cylinder <NUM> may be supported by a conventional swing-out cylinder crane mechanism <NUM> in one embodiment including an upper support tube <NUM> received through the hub of the cylinder and a lower retaining pin <NUM> removably received through an aperture of the crane and housing <NUM>. Cylinder crane <NUM> is used to pivot cylinder <NUM> outwards from cylinder housing <NUM> from a ready-to-fire position wherein the cylinder is positioned in the housing and one chamber <NUM> of the cylinder may be aligned with barrel <NUM>, to a lateral loading position for loading cartridges into chambers <NUM> wherein the cylinder is laterally displaced from the housing to expose the chambers. Crane latch <NUM> operates to release and swing cylinder <NUM> outwards for spent casing ejection and reloading. In other possible embodiments, the revolver however may have a tilting break-open type cartridge loading mechanism with a pivoting cylinder and barrel assembly which is also well known in the art rather than a swing out cylinder. Either design may be used and is not limiting of the present invention.

Barrel <NUM> extends axially forward from housing <NUM> of the revolver <NUM> and defines an internal bore <NUM> for guiding the projectile (e.g. slug or bullet) towards the front muzzle end of the barrel. The bore of the barrel <NUM> which defines the projectile passageway defines a longitudinal axis LA of the firearm. The barrel may be a two-pieced shrouded barrel design in some embodiments having an external shroud and internal barrel insert, or a single-piece unshrouded barrel. Either design may be used and is not limiting of the present invention.

Revolver <NUM> further includes a conventional spring-biased ejector <NUM> for ejecting spent cartridge casings from the revolver. Ejector <NUM> is disposed at the rear of cylinder <NUM> and is configured to operably engage the rim of the spent cartridge casing in the cylinder after firing all rounds. An ejector rod <NUM> carried by the cylinder is operably coupled to ejector <NUM> via a tube 22a of the ejector which through the hub of the cylinder <NUM>. An ejector spring (not shown) biases ejector rod <NUM> forward and may be depressed by a user to eject spent cartridge casings from the revolver cylinder <NUM> in a conventional manner.

Revolver <NUM> in an exemplary embodiment includes a firing control mechanism supported by the housing <NUM> and operable to discharge the firearm. The firing control mechanism generally includes the following firing control components: trigger <NUM>, hammer <NUM>, cylinder lock <NUM>, hammer lever or dog <NUM>, pawl <NUM>, and mainspring assembly including mainspring <NUM>. In one embodiment, mainspring assembly includes mainspring strut <NUM> having an upper end engaging hammer <NUM> and a lower end braced against the grip portion of housing <NUM>. Mainspring <NUM> biased the hammer towards the forward firing position. Pawl <NUM> may be pivotably mounted to trigger <NUM> via pin 35a and is arranged to engage the cylinder ratchet <NUM> which rotates the cylinder to the next position each time the trigger is pulled. Pulling trigger <NUM> rearward raises the pawl which engages and rotates the cylinder to align an active one of the chambers <NUM> with the firing pin and barrel bore <NUM>. In conventional manner, the cylinder <NUM> is locked in the aligned position via cylinder lock <NUM> engaging one of the plurality of circumferentially spaced locking notches <NUM> formed on the exterior of the cylinder (see, e.g. <FIG> and <FIG>). Cylinder lock <NUM> is mounted about pinned connection <NUM> to revolver housing <NUM> and is actuated automatically by trigger <NUM> when pulled.

Hammer dog <NUM> is essentially a spring-biased lever that is pivotably mounted to hammer <NUM> about a pinned connection <NUM> and is operably positioned between trigger <NUM> and hammer <NUM>. The lower end of hammer dog <NUM> is biased forward toward trigger <NUM> by a spring-plunger assembly including spring <NUM> to engage rear operating extension arm <NUM> of the trigger. Hammer dog <NUM> is engaged by and rotated upwards by trigger <NUM> in response to a trigger pull to partially cock the hammer when firing the revolver in double action mode. Specifically, top cam surface 11a formed on trigger <NUM> engages the hammer dog during the initial phase of the trigger pull, as further described herein. Cam surface 11a may be rounded to smoothly engage and operate the hammer dog <NUM>.

Referring to <FIG>, hammer <NUM> is pivotably mounted to housing <NUM> rearward of the cylinder <NUM> about a pinned connection formed by laterally-extending transverse hammer pivot pin <NUM>. The lateral direction is defined as extending side to side in the firearm and perpendicularly to longitudinal axis LA. The pivot pin <NUM> defines a pivot axis of the hammer. Hammer pivot pin <NUM> has an elongated cylindrical body with circular cross-sectional shape and is received in a transversely extending pivot pin hole <NUM> in the housing and corresponding hole 101a in hammer <NUM>. Hammer pivot pin <NUM> preferably may be fixed/stationary and non-rotatable relative to the housing in one embodiment. In one implementation, the pivot pin <NUM> may be fixed in position by an anti-rotation protrusion <NUM> extending radially and perpendicularly to the cylindrical body of the pin. Anti-rotation protrusion <NUM> may have a flattened plate or flange-like oblong body in one embodiment. Protrusion <NUM> engages a complementary configured fixation slot <NUM> formed in the outer surface of the housing <NUM> which prevents rotation of the hammer pivot pin relative to the housing such that the pin does not rotate when the hammer is rotated between the cocked and firing positions as the action of the revolver is cycled to discharge the firearm. Other shaped anti-rotation protrusions and mating fixation slots may be used which differ from the illustrated embodiment. In other possible embodiments, the anti-rotation protrusion may be formed on the housing and the complementary configured fixation slot on the hammer pivot pin <NUM>. In yet other possible embodiments, the opposite end portions of the cylindrical shaft of the pivot pin <NUM> may be non-circular in cross section (e.g. hexagonal, octagonal, square, etc.) and the cross-sectional shape of the pivot pin hole <NUM> in the housing at a corresponding location may be complementary configured to match which would prevent relative rotation between the hammer pivot pin and its pivot pin hole.

In some embodiments, the hand grip <NUM> when attached to the downward extending rear grip portion of housing <NUM> such as grip tang <NUM> (see, e.g. <FIG>) may be configured to assist with retaining the hammer pivot pin <NUM> in the firearm housing <NUM>. As shown in <FIG>, a portion of the grip <NUM> may at least partially overlap the anti-rotation protrusion <NUM> to prevent the pin <NUM> from working its way outward from the housing due to vibration from repeated firing of revolver <NUM> or drops. In addition to or instead of the interference created by the grip overlap, some embodiments may include a semi-circular shaped locking clip <NUM> shown in <FIG> and <FIG>. A C-shaped semi-circular spring clip may be used in some embodiments for the clip <NUM>; however, other suitable shapes and types of clips may be used. Locking clip <NUM> is mutually engaged with mating circumferential locking grooves <NUM> and <NUM> formed inside hammer pivot pin hole <NUM> and the shaft of hammer pivot pin <NUM>, respectively. Before inserting the hammer pivot pin <NUM> into the pivot pin hole <NUM>, the clip <NUM> may be inserted over the shaft of the pin to engage groove <NUM>. When the pivot pin <NUM> is inserted into its pivot pin hole <NUM> in housing <NUM>, the clip will then engage the opposing groove <NUM> in the pivot pin hole <NUM> to secure the pivot pin to the housing. This arrangement assists with retaining the hammer pivot pin <NUM> in the firearm housing <NUM> regardless of the configuration of the hand grip <NUM>. Either the grip <NUM> or locking clip <NUM> may be used to resist withdrawal of the hammer pivot pin <NUM> from the pivot pin hole <NUM> in housing <NUM>.

As shown in <FIG> and <FIG>, hammer <NUM> is movable in rearward and forward arcuate motions between a ready-to-fire rearward cocked position and a forward firing position for striking transfer bar <NUM> (or alternatively firing pin <NUM> directly in those embodiments without a transfer bar). Hammer <NUM> is biased forward towards firing position by mainspring <NUM> mounted to the housing <NUM>. Hammer has elongated body including an upper striking portion <NUM> configured for striking transfer bar <NUM> (or alternatively firing pin <NUM> directly) and an enlarged lower operating portion <NUM> (see, e.g. <FIG>). Striking portion <NUM> in one embodiment may include an outwardly extending spur <NUM> for manually cocking the hammer <NUM>; however, in other embodiments the hammer may be spur-less and completely internal without a spur that protrudes outwards beyond the housing of the firearm.

Trigger <NUM> in one non-limiting embodiment as illustrated in <FIG> may be pivotably mounted to a trigger housing <NUM> (or alternatively direction to housing <NUM> in other embodiments) about a pinned connection formed by pivot pin <NUM> and moves arcuately in response to a trigger pull by a user. The trigger housing <NUM> is in turn mounted to the housing by any suitable means. Trigger <NUM> is biased downwards and forward towards the unpulled state by trigger spring assembly <NUM>. Trigger <NUM> has a body including a downwardly extending grasping portion 11d configured for engaging the user's finger and rearwardly projecting operating extension arm <NUM> selectively engageable with both the hammer dog <NUM> and forwardly extending operating foot 18a of the hammer. Extension arm <NUM> defines cam surface 11a which is engageable with the hammer dog <NUM> and a sear edge 11b below that engages the hammer operating foot 18a to further cock and ultimately release the hammer <NUM> as the trigger is pulled fully rearward to discharge the firearm. A rearwardly open cutout 11e is formed between cam surface 11a and sear edge 11b to spatially separate these features. In one embodiment, the hammer operating foot 18a is configured to partially enter the cutout 11e as the trigger is pulled (see, e.g. <FIG>). The hammer operating foot 18a also enters the cutout when the hammer is at rest in the forward position and the trigger is unpulled.

In operation when trigger <NUM> is pulled in double action firing mode, operating extension arm <NUM> projecting rearwards from the trigger (i.e. cam surface 11a) engages hammer dog <NUM>, which in turn rotates and cocks hammer <NUM> partially rearwards. As the trigger is pulled further rearward, sear edge 11b of trigger <NUM> next engages operating foot 18a of the hammer as the trigger disengages the hammer dog. Pulling the trigger fully further cocks the hammer to the release point in which the trigger extension arm <NUM> disengages the hammer which rotates forward to the firing position to discharge the firearm. If operating in single action mode, the user may manually draw the hammer back to the cocked position which will remain there until the trigger is pulled to release the hammer and complete the firing sequence.

Referring to <FIG>, the firing control mechanism of revolver <NUM> may optionally include a safety transfer bar <NUM> in certain embodiments. Transfer bar <NUM> is vertically movable in response to a trigger pull and reduces the likelihood that the revolver will fire in the absence of a trigger pull. In one embodiment, transfer bar <NUM> may be positioned forward of hammer dog <NUM> and is movably coupled to trigger <NUM> via a pinned connection. Spring-biased firing pin <NUM> is received in a recess formed in revolver housing <NUM> and axially movable therein to strike a cartridge when loaded in chamber <NUM>. When trigger <NUM> is pulled, transfer bar <NUM> moves vertically upwards in response and becomes positioned between hammer <NUM> and firing pin <NUM>. This fills a gap between the upper striking portion of the hammer an the rear end of the firing pin (see, e.g. <FIG>). As hammer <NUM> becomes fully cocked and is then released as described herein, the hammer strikes transfer bar <NUM> which in turn transfers the force to firing pin <NUM> propelling it forward to strike the chambered cartridge. In the absence of a trigger pull without the intervening safety transfer bar <NUM> in place, hammer <NUM> preferably is incapable of reaching firing pin <NUM> when the hammer is in its released forward-most position. In some embodiments, the transfer bar <NUM> may be omitted and the hammer <NUM> may be configured to strike the firing pin <NUM> directly. Accordingly, the hammer may be considered as striking the firing pin whether directly or indirectly via the intermediate transfer bar.

The hammer-blocking safety mechanism according to the present disclosure will now be described. Referring generally to <FIG>, the safety mechanism includes blocking member such as a blocking pin <NUM> in one embodiment movably mounted to lower operating portion <NUM> of hammer <NUM>. Blocking pin <NUM> is slideably mounted in a generally upwardly extending pin bore <NUM> formed in the hammer. Pin bore <NUM> has a downwardly open end and an upwardly open end in communication with transverse pivot pin hole <NUM> which receives hammer pivot pin <NUM>. Pin bore <NUM> intersects pivot hole <NUM> to allow the blocking pin <NUM> to access the hammer pivot pin <NUM> and engage a blocking feature thereon such as a blocking notch <NUM> in one embodiment. In one embodiment, the centerline CL2 of pin bore <NUM> may be offset from the centerline CL1 of the hammer pivot pin hole <NUM> as shown in the illustrated embodiment. The offset provides engagement between the side of the elongated blocking pin body with the blocking notch <NUM> to ensure a positive mutual engagement for arresting the hammer. In one embodiment, the pin bore <NUM> may extend completely through the hammer body from one side to an opposing side (see, e.g. <FIG>).

<FIG> show blocking pin <NUM> in greater detail. Blocking pin <NUM> may include an elongated cylindrical body or shaft and a radially projecting and diametrically enlarged annular retention flange <NUM>. Flange <NUM> may be circular and arranged proximate to the outermost end of the blocking pin. Pin bore <NUM> includes a smaller diameter section 111a adjoining the hammer pivot pin hole <NUM> and an adjoining larger diameter section 111b slideably receiving the diametrically enlarged retention flange <NUM> of the blocking pin. An annular stepped shoulder <NUM> separates the smaller and larger diameter sections as shown. A biasing spring <NUM> disposed in the larger section of pin bore <NUM> acts on the retention flange to bias the blocking pin away from the hammer pivot pin <NUM>. The blocking pin is retained in its pin bore by an expandable retaining clip <NUM> which engages the flange (see, e.g. <FIG>). A C-shaped clip may be used in some embodiments; however, any other configuration of clip suitable for this purpose may be used. The clip prevents spring <NUM> from ejecting the blocking pin <NUM> from bore <NUM>. Other type retention means including other type and/or shaped clips, threaded caps/screws, pins, etc. may be used to removably retain the blocking pin <NUM> in its pin bore <NUM>. One end of spring <NUM> acts on flange <NUM> and the opposite end acts on shoulder <NUM>. Spring <NUM> may be a coiled compression spring in one embodiment; however, other type springs may be used in other arrangement.

Blocking pin <NUM> is configured and operable to act on hammer pivot pin <NUM> to completely arrest motion of the hammer <NUM>, or partially arrest rotation of the hammer by substantially slowing movement of the hammer <NUM> such that it cannot transfer its stored energy to the chambered cartridge sufficiently to detonate the cartridge. The terms "arrest" or related forms as used herein should be broadly construed as including either of the foregoing scenarios which may be considered as blocking the hammer to prevent discharge of the firearm. Blocking pin <NUM> may be transversely oriented to the hammer pivot pin <NUM>, such as without limitation perpendicularly in some embodiments as shown.

In one embodiment, hammer pivot pin <NUM> includes a mating blocking feature such as slot-shaped blocking notch <NUM> formed in the cylindrical body of the pin which is selectively engageable with blocking pin <NUM> when the safety mechanism is automatically activated. In one embodiment, notch <NUM> may comprise a flat blocking surface <NUM> arranged to engage the cylindrical side of the blocking pin. The notch <NUM> with flat blocking surface may be formed by any suitable method, such as without limitation cutting or milling away a portion of the diameter of the cylindrical hammer pivot pin <NUM> to a desired depth to produce a flat. The depth of the notch measured to the blocking surface <NUM> from the full diameter portion of the hammer pivot pin body may be s between about <NUM>-<NUM> percent of the full diameter of the hammer pivot pin <NUM> in some embodiments. In one non-limiting example, the depth of the notch may be about <NUM>% of the full diameter of the hammer pivot pin <NUM>. This is sufficient to arrest or retard/slow rotation of the hammer <NUM> so that it cannot either reach the rear end of the firing pin <NUM>,or lightly engages the firing pin (or transfer bar if provided) without sufficient force to detonate a chambered cartridge. Other configurations of blocking notch <NUM> may be used in other embodiments. For example, without limitation, in lieu of a flat blocking surface as depicted in the notch <NUM>, blocking surface <NUM> may be concavely curved in other embodiments and complementary configured to the radius/curvature of the blocking pin shaft for a curved-to-curved interface in lieu of flat-to-curved interface. Accordingly, there are many possibilities and the blocking notch configuration is expressly not limited to that illustrated.

Other configurations of a blocking member not limited to a straight cylindrical member such as blocking pin <NUM> are possible to engage a mating blocking feature on the hammer pivot pin <NUM>. In some various other embodiments contemplated, the blocking member may be a straight shaft or pin with polygonal cross section (e.g. square, hexagonal, octagonal, etc.), non-polygonal other than circular cross section (e.g. oval/ellipsoidal), L-shaped, a pin or lever that pivotably rotates about its own separate pivot axis on the hammer, etc. The hammer pivot pin <NUM> therefore would have a blocking featured configured to cooperate with these possible alternative configurations of blocking members to arrest the motion of the hammer. Accordingly, neither the blocking member nor notch are limited to the blocking pin and blocking notch disclosed herein.

The blocking pin <NUM> is linearly moveable between a retracted non-blocking position misaligned and not blockingly engageable with the blocker notch <NUM> (i.e. blocking surface <NUM>) of the hammer pivot pin <NUM>, as shown in <FIG> and a projected blocking position aligned and blockingly engageable with the blocking notch, as shown in <FIG>. Spring <NUM> acts to bias the blocking pin towards the retracted non-blocking position. Because the centerline CL1 of the hammer pivot pin hole <NUM> in hammer <NUM>\ (and concomitantly hammer pivot pin <NUM>) is offset from the centerline CL2 of the blocking pin bore <NUM> (and concomitantly blocking pin <NUM>), the cylinder side of the blocking pin shaft is positioned to engage the flat blocking surface <NUM> of the hammer pivot pin <NUM> when the blocking pin is in the projected blocking position.

The position of the blocking pin <NUM> is controlled by the rotational position of the hammer <NUM>. When the hammer of the double action revolver <NUM> is not in the cocked position, the blocking pin <NUM> is captured between the retaining clip <NUM> and the full diameter portion of the hammer pivot pin <NUM> as seen in <FIG>, thereby preventing deployment of blocking pin. As shown, blocking pin <NUM> is therefore also not aligned to move and engage blocking notch <NUM> of hammer pivot pin <NUM> if the revolver <NUM> were dropped or otherwise impacted. When the hammer is in the fully cocked position represented in <FIG>, the blocking pin <NUM> is captured by the retaining clip in one direction but is now aligned with the blocking <NUM> notch in the hammer pivot pin <NUM>. Accordingly, the blocking pin <NUM> is only restricted from linear movement in the direction towards the blocking notch <NUM> of the hammer pivot pin <NUM> by force of the spring <NUM>. In the case that the firearm is then dropped or otherwise impacted, the momentum of the blocking pin <NUM> will create maximum movement of the blocking pin from the non-blocking to blocking position when the centerline axis C2 of the pin <NUM> is substantially vertically oriented on contact with or by a hard surface (see, e.g. <FIG>). As the axis C2 of the blocking pin deviates from vertical, the resulting sliding movement of the blocking pin to the blocking position may be reduced but still sufficient to actuate and move the pin when the blocking pin is oriented at an angle A1 up to and including about <NUM> degrees to vertical (VA). If the firearm drop or impact condition causes the hammer to disengage from the trigger <NUM> when the blocking pin <NUM> is in the deployed blocking position , the blocking pin will move in an arcuate path with the lower operating portion <NUM> of the hammer <NUM> until the blocking pin abuttingly engages the blocking notch <NUM> in the stationary hammer pivot pin <NUM> (see, e.g. <FIG>). This engagement arrests further movement of the hammer sufficient to discharge the firearm. This engagement will stop the rotation of the hammer and prevent the hammer from reaching the firing pin (or transfer bar) and transferring impact energy to the cartridge. This may be accomplished by either: (<NUM>) holding the hammer in this blocked position preventing any substantial motion thereof initially, (<NUM>) allowing the hammer to move slightly and rebound off the blocking pin upon engagement to hold the hammer in the blocked position without reaching and striking the firing pin or intermediate transfer bar <NUM>, or (<NUM>) slowing/retarding the speed of the hammer rotation to reduce energy transferred to the firing pin below the level required to detonate the chambered cartridge. All three blocking scenarios will prevent the firearm from discharging. While a hammer pivot pin <NUM> with complete blockage of rotation may be shown, any blocking engagement between the blocking pin <NUM> and blocking notch <NUM> of the hammer pivot pin <NUM> that slows or robs sufficient energy from the hammer to prevent discharge of the firearm could also be used.

The speed and displacement of the blocking pin <NUM> are dependent on many factors including without limitation the mass of the blocking pin, the stiffness of the blocking pin spring <NUM>, the orientation of the blocking pin, and in the case of a drop, the height, orientation and condition of the contact surface. The mass of the blocking pin and the spring design are mutually selected to allow the momentum and mass of the blocking pin to move under a wide range of impact conditions to overcome the spring force, such as at different drop heights and impact angles. During these events, the blocking pin <NUM> will move from the retracted (resting) position until it reaches either full travel in pin bore <NUM> or at least contacts the blocking notch <NUM> of hammer pivot pin <NUM> when moved to the projected position. After reaching full travel if it has not contacted the notch <NUM> of the hammer pivot pin <NUM>, the blocking pin spring <NUM> will return the blocking pin back to the starting retracted position.

Depending on the distance that the blocking pin <NUM> travels and the rotational speed of the hammer <NUM>, the hammer may be stopped as the blocking pin is traveling away from the starting retracted position or as it returns. The distance that the blocking pin can travel is also important because the farther the pin can travel, the more time the hammer has to contact the blocking pin. If desired, in other possible embodiments it could be possible in some applications to have a second blocking pin operating on the same centerline axis C2 as the first blocking pin, but activated in the opposite orientation. It may also be possible in other embodiments to add other blocking pins in different orientations provided the hammer pivot pin <NUM> can be notched in the same direction as the other pins. It would also be possible in some embodiments to replace the notch <NUM> in the hammer pivot pin <NUM> with a transversely oriented hole (to the centerline of the pin) contained within the hammer pivot pin in or through which the blocking pin <NUM> is insertable when the pin moves to its projected position when the firearm is dropped/impacted. Engagement between the pin and blocking hole of the hammer pivot pin arrests motion of the hammer <NUM>. The blocking hole may be formed between opposing sides of the hammer pivot pin.

In the event the blocking pin <NUM> is activated, and the hammer <NUM> is stopped and held by the blocking pin, the firearm will not be able to be fired. The hammer must be moved back towards the cocked position to take the load off of the blocking pin and allow the spring <NUM> to move the blocking pin back out of the way of the hammer pivot pin. At this time, the firearm could be fully cocked and fired, or the hammer could be lowered/moved forward to the un-cocked (forward firing) position. In some double action revolvers, it may be possible to position the blocking pin in such a way as to allow the pulling of the trigger to cock the hammer, thereby disengaging and releasing the blocking pin from the hammer pivot pin blocking notch <NUM> which returns the blocking pin to the retracted position and firing the revolver. In other firearms it may be necessary to cycle the action using whatever means is appropriate for that type of firearm.

In other situations, the hammer <NUM> might rebound after the blocking pin impact, which would allow the blocking pin to reset and then let the hammer fall to the uncocked forward firing position. If this occurs, either the hammer will not have enough energy remaining to fire the cartridge or contact other intermediary elements, such as the transfer bar <NUM> previously described herein if provided, which will prevent the hammer from contacting the firing pin or transfer bar. If this occurs the user would be able to cock the hammer in single action or double action mode and continue firing the revolver.

The blocking pin <NUM> preferably is made of a metallic material capable of withstanding impact loads. In some embodiments, the blocking pin <NUM> may also optionally be finished on its exterior surface with an anti-friction coating such as nickel Teflon or other to reduce friction and drag between the pin and hammer pivot pin blocking notch and pin bore <NUM>. While all of the concepts shown and discussed so far rely on a sliding blocking pin <NUM> and a stationary or fixed hammer pivot pin <NUM>, the same concept may be applied to designs that do not use a sliding blocking pin. The simplest description of the mechanism may include a fixed or rotationally restricted hammer pivot pin, working in conjunction with additional part or parts integrated within the hammer assembly, that when moved by specific momentum based loading conditions, creates sufficient contact between the hammer assembly and the pivot pin to stop or restrict rotational motion of the hammer. One different non-limiting example of this would be a hammer blocking component the pivots about an axis in lieu of slides linearly as previously described herein, other than the axis of the hammer pivot pin. The pivotable blocking component thus would be used in place of the sliding blocking pin <NUM>. In other embodiments, it would also be possible to replace the blocking pin spring <NUM> with a detent type feature, or a magnet, to hold the blocking pin or other component in the inactive position.

An exemplary method for blocking a firing mechanism of a firearm will now be described. The method begins by providing the firearm which may be a revolver <NUM> in one embodiment having a firing mechanism including hammer <NUM> mounted and movable about hammer pivot pin <NUM> between rearward cocked and forward firing positions as previously described herein. The trigger <NUM> is operable to cock and release the hammer. Slideably movable blocking pin <NUM> is mounted to the hammer, generally and substantially below hammer pivot pin <NUM>.

The method may continue by positioning the hammer <NUM> in the firing (forward) position. In this position, the blocking pin <NUM> is misaligned with blocking notch <NUM> on the hammer pivot pin <NUM> (see, e.g. <FIG>). If the firearm were impacted by a hard bump or being dropped on a relatively hard surface, the blocking pin <NUM> would attempt to move in its pin bore <NUM> but would be blocked by part of the full diameter portion of the cylindrical pin body or shaft such that the blocking pin cannot access the blocking notch.

The method may continue by rotating the hammer <NUM> to the cocked position shown in <FIG>. Rotating the hammer results in aligning the blocking pin <NUM> with the blocking notch <NUM> on the hammer pivot pin <NUM> such that the blocking pin is now able to slide towards the hammer pivot pin <NUM> and engage the blocking notch. It bears noting that <FIG> shows the blocking pin being unactuated and in the non-blocking position.

The next action which may occur is impacting the firearm on a relatively hard surface, such as by dropping the firearm or bumping it without a drop while the hammer <NUM> is cocked. The impact force on the firearm automatically actuates and moves the blocking pin <NUM> from the retracted non-blocking position disengaged from the blocking notch <NUM> of the hammer pin <NUM> to a projected blocking position shown in <FIG> in which the blocking pin slideably moves to engage the blocking notch <NUM> of the hammer pivot pin. The blocking pin is thus now actuated via the impact force. This results in arresting rotation of the hammer <NUM> from the cocked to forward firing position to prevent discharging the firearm via the blocking pin engagement with the blocking notch. As the hammer <NUM> tries to rotate forward, the shaft of the hammer pivot pin <NUM> at blocking notch <NUM> will be blocked by the blocking pin <NUM> as shown in <FIG>. The blocking pin <NUM> may remain automatically engaged with the blocking notch <NUM> and hammer pivot pin <NUM> until released due to the main spring <NUM> which always biases and attempts to move the hammer <NUM> forward to the firing position.

The user may then disengage and release the blocking pin <NUM> from hammer pivot pin <NUM> (i.e. blocking notch <NUM> thereon) by manually cocking and rotating the hammer slightly rearward. Spring <NUM> will then automatically return the released blocking pin <NUM> to its retracted non-blocking position shown in <FIG> even though the hammer remains cocked.

It bears noting that in the case of a single action revolver, the user must manually cock the hammer which remains there until the trigger is pulled to release it and discharge the firearm. In the case of a double action revolver, the user may optionally manually cock the hammer as well which simulates the foregoing single action operation. Normally for a double action revolver, fully pulling the trigger both rotates the hammer to the cocked position and then releases the hammer to discharge the firearm as the hammer is drawn farther and farther rearward by the trigger pull. Some users prefer to use a double action revolver in the simulated single action mode by manually cocking the hammer since a lighter trigger pull force can release the hammer than when shooting in double action mode. This translates into greater shooting accuracy. The present hammer-blocking safety mechanism is intended to disable firing of the firearm when the revolver is impacted in the single action mode with already cocked hammer, whether either a single action revolver or double action revolver is being used.

In implementations where the present safety mechanism is used on a hammer-fired semiautomatic pistol or rifle, the hammer is automatically maintained in the rearward cocked between firing rounds. The blocking pin <NUM> therefore will deploy to arrest the hammer if the firearm is dropped or otherwise impacted.

Claim 1:
A firearm (<NUM>) with safety mechanism comprising:
a housing (<NUM>);
a spring-biased hammer (<NUM>) rotatably supported by a transverse hammer pivot pin (<NUM>) fixed in position relative to the housing, the hammer movable between a rearward cocked position and a forward firing position;
a trigger (<NUM>) operable to release the hammer (<NUM>) from the cocked position to discharge the firearm (<NUM>);
a blocking notch (<NUM>) formed on the hammer pivot pin (<NUM>); and
a hammer blocking pin (<NUM>) movably mounted to the hammer (<NUM>) and selectively engageable with the blocking notch (<NUM>);
wherein rotating the hammer (<NUM>) from the firing position to the cocked position aligns the blocking pin (<NUM>) with the blocking notch (<NUM>) of the hammer pivot pin (<NUM>) such that the blocking pin is movable to engage the blocking notch;
wherein the blocking pin (<NUM>) is linearly and slideably moveable between a retracted non-blocking position, and a projected blocking position engageable with the blocking notch (<NUM>); and
a spring (<NUM>) biasing the blocking pin (<NUM>) towards the retracted position; and wherein the blocking pin automatically moves from the retracted position to the projected position when the hammer (<NUM>) is in the cocked position which aligns the blocking pin with the blocking notch (<NUM>) and the firearm (<NUM>) is dropped or impacted on a surface.