Patent Publication Number: US-8984788-B2

Title: Unitary sear housing block

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a divisional of U.S. patent application Ser. No. 13/294,531, filed Nov. 11, 2011, which is based upon and claims the benefit of priority to U.S. Provisional Patent Application No. 61/429,330, filed Jan. 3, 2011, both applications being hereby incorporated by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to firearms and, more particularly, to firearm frames and frame components. 
     BACKGROUND 
     Most semiautomatic handguns include a frame and a slide that moves along the firearm&#39;s longitudinal firing axis in a reciprocating manner. The frame provides the core support structure for the firearm&#39;s operational and other components, e.g., trigger and firing mechanisms, grip, ammunition feeding system, barrel, and slide. For operably attaching the slide to the frame, the frame includes a set of rails positioned on opposite longitudinal sides of the frame. The rails are integral with the rest of the frame, i.e., the frame, including the rails, is machined or otherwise formed from a single piece of metal or other material. 
     In addition to the rails, the frame includes other integrally machined features for attaching, supporting, and/or guiding additional components of the firearm such as the trigger and firing mechanism sear. While such features (including the rails) function well from an operational standpoint, the manufacturing process for forming the rails and other integral features can be time consuming and complex. 
     In conventional assembly practices, close measurement and adjustment of sear-to-striker height and longitudinal positioning (typically either by replacement or by remachining of parts) may be required due to variations of several assembly and manufacturing parameters within achievable tolerances. In particular, sear-to-striker height may be affected by the following parameters: the location of the striker with reference to the slide rails, the mating fit of the slide rails with respect to the slide locating rails, the location of the sear housing block relative to the slide locating rails, the sear pivot location within the sear housing block, and the height of the sear itself. Relative longitudinal positioning of the sear and striker within the frame may be affected by several of the above-mentioned parameters, as well as by the longitudinal position of the sear housing block within the frame. 
     Consequently, it has been conventional to fully assemble an auto-loading pistol and to then check sear-to-striker height, longitudinal positioning, and operation of the firing mechanism within the fully assembled pistol. Measurement of sear-to-striker height within an assembled pistol, and the occasional requirement to remove and replace or re-machine one or more assembled components in order to meet operational tolerances, however, lead to additional labor and expense in manufacturing of autoloading pistols. 
     Accordingly, it has long been appreciated that it would be advantageous to better control sear-to-striker height and relative longitudinal positioning during assembly of auto-loading pistols. 
     SUMMARY 
     In embodiments of the present invention, a firearm includes a firearm frame and a unitary sear housing block. The frame has at least one receptacle formed therein, with the unitary sear housing block being removably received in the receptacle. For example, the receptacle may be an upwardly open compartment integral with the frame and accessible from the top of the frame, and the unitary sear housing block may be configured for “drop-in” insertion into the compartment. The unitary sear housing block is configured for accommodating one or more operational components of the firearm, e.g., triggers, trigger bar, sear assemblies, or the like. That is, one or more firearm components may be operably attached to and I or housed in the unitary sear housing block. In assembling the firearm, the operational components are attached to the unitary sear housing block, the unitary sear housing block is dropped into the receptacle, and the unitary sear housing block is secured in place. 
     In another embodiment, the unitary sear housing block is provided with a set of slide rails. The slide rails partially or wholly replace the slide rails typically integrally formed on a firearm frame. A slide portion of the firearm moves along the slides in a reciprocating manner during operation of the firearm. 
     In embodiments of the present invention, a unitary sear housing block assembly for an auto loading pistol includes a sear positioning housing, a sear pivot hole, frame locating grooves and slide locating rails formed with reference to the sear pivot hole, and a frame pin hole formed with reference to the frame locating grooves and the slide locating rails. 
     In embodiments of the present invention, the frame locating grooves are shaped and positioned to matingly contact complementary rails formed in an autoloading pistol frame while the frame pin hole is aligned to corresponding holes formed through the pistol frame. The frame locating grooves thereby aid in positioning the unitary sear housing block assembly within the pistol frame. 
     In embodiments of the present invention, the slide locating rails are shaped and positioned to align with corresponding slide locating rails or tabs formed on the pistol frame while the frame pin hole is aligned to corresponding holes formed through the pistol frame and the frame locating grooves are mated to the complementary surfaces of the pistol frame. 
     Advantageously, by incorporating the frame locating grooves and slide locating rails into the sear housing block, the unitary sear housing block assembly eliminates assembly dimensional variances between the sear housing block and the slide rails, thus reducing as-assembled variances in sear-to-striker height. 
     Additionally, a firearm including a unitary sear housing block may utilize a “generic” frame provided without integral rails or other features for supporting the sear and slide. Instead, the rails are provided as part of the unitary sear housing block configured to support the firing mechanism. During assembly, the unitary sear housing block may be simply inserted into the frame, at an appropriate pre-configured receptacle, and secured in place. 
     Additionally, the unitary sear housing block also incorporates the ejector into the sear housing block, thus lowering the total part components making for a more consistent part assembly while lowering the overall cost of the part. 
     These and other objects, features and advantages of the present invention will become apparent in light of the detailed description of the best mode embodiment thereof, as illustrated in the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified schematic side view of a semiautomatic pistol; 
         FIG. 2  is a simplified schematic side elevation view of the pistol of  FIG. 1  shown with the slide moved to a rearward position on the pistol frame; 
         FIG. 3  is a simplified schematic perspective view of a firing mechanism and unitary sear housing block of a semiautomatic pistol according to an embodiment of the present invention; 
         FIGS. 4 and 5  are detail perspective views of the unitary sear housing block shown in  FIG. 3 ; and 
         FIG. 6  is a simplified schematic view of the semiautomatic pistol of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1 and 2 , one exemplary embodiment of a semiautomatic pistol or firearm with a unitary sear housing block of the present invention is shown generally at  10  and is hereinafter referred to as “firearm  10 .” The firearm  10  comprises a frame  12 , a slide  14 , and a fire control mechanism that operates via actuation of a trigger  16 . The frame  12  is fabricated of a high-impact polymer material, metal, or a combination of polymer and metal. The slide  14  houses a barrel  18  in the forward end thereof. The barrel  18  is cooperatively linked with the slide  14  and, together with the slide  14 , defines a longitudinal firing axis  20 . A rearward end of the barrel  18  is adapted for receiving an ammunition cartridge  22 . 
     The slide  14 , which is defined by a slide frame  26 , further includes a breech face  28  and an ejection port  30 . The breech face  28  is engagable with the rearward end of barrel  18  to form a firing chamber when the slide  14  is disposed forwardly on the frame  12  ( FIG. 1 ). An ejection mechanism included in the slide  14  provides for the ejection of a cartridge casing  22  upon firing the firearm  10  or manually cycling the slide  14 . 
     Referring now to  FIG. 3 , the firearm further comprises a trigger mechanism housing  32  and a unitary sear housing block  34 . The trigger mechanism housing  32  and unitary sear housing block  34  together support portions of a fire control mechanism generally shown at  40 . In the exemplary embodiment of  FIGS. 1-6 , for purposes of illustration, the fire control mechanism  40  is of a striker-type configuration and comprises a striker-type striker  42  having a striker portion  43  and a depending leg  44 . However, the present invention can be adapted for use with different types of firing mechanisms, and is not meant to be limited to a particular type of firing mechanism. 
     Still referring to  FIG. 3 , the exemplary fire control mechanism  40  further includes a sear assembly  46  and a trigger assembly  48 . The sear assembly  46  has a sear  50  pivotally mounted onto a sear pin  51 , such that an upper end of the sear  50  may engage the striker  42 . The trigger assembly  48 , which functions to actuate the sear  50 , includes a trigger  52  pivotally connected to the trigger mechanism housing  32 , and a trigger bar  54  pivotally connected to the trigger  52  via a pin  56 . The trigger bar  54  connects the trigger  52  and the sear assembly  46 . The trigger  52  may be of a multiplepiece articulated construction, as shown, or of unitary construction. 
     When the trigger  52  is actuated by being pressed in a rearward direction, the trigger  52  pivots about a pin  64  that extends through a lateral opening  66  in the trigger mechanism housing  32 . This transmits movement to the trigger bar  54  via the pin  56 . The trigger bar  54  is thereby moved in a rearward direction for actuation of the sear  50 . When actuated, the sear  50  pivots rearwardly about the sear pin  51 , thereby releasing its engagement with the striker  42 . 
     The trigger mechanism housing  32  is a generally open frame-like support having first and second sidewalls  70 ,  72  interconnected by one or more lateral cross members  74 . The sidewalls  70 ,  72  are provided with various laterally aligning openings, e.g., the lateral opening  66 , for attachment of various subcomponents and/or for attachment of the trigger mechanism housing  32  to the frame  12 . As noted, the interior of the trigger mechanism housing  32  is generally open, to accommodate the trigger  52  as well as any other components configured for disposition between the two sidewalls  70 ,  72 . 
     The unitary sear housing block  34  is a generally solid body having a number of openings, slots, etc. formed therein for accommodating the various components of the sear assembly  46 . Detailed views of the unitary sear housing block  34  are shown in  FIGS. 3-5 . The particular number of openings and slots in the unitary sear housing block  34 , and their dimensions I configurations, will depend on the particular nature and configuration of the sear assembly components, which, of course, will depend on the type of sear assembly utilized. For example, as shown in  FIGS. 4 and 5 , the unitary sear housing block  34  may have a longitudinal slot  47  formed therein for accommodating the sear  50 , as well as, the passage of the depending leg  44  of the striker  42  and of the trigger bar  54 . 
     For reciprocal movement of the slide  14  along the frame  12 , the sear housing block  34  has a pair of rear slide rails  80 ,  82  attached to, and extending laterally outwards from, opposite upper side edges of the unitary sear housing block  34 . The slide rails  80 ,  82  are substantially identical in shape, and are dimensioned to fit within opposed, inwardly opening and longitudinally extending grooves (not shown) located on the inner surface of the slide  14 . The slide rails may have arcuate, convex bottom surfaces  100  and/or chamfered or rounded leading and trailing edges  102  to prevent the slide  14 , upon discharge of the firearm  10 , from the possibility of binding or overstressing the housings  32 ,  34 . An ejector bar  103  is formed integrally with the sear housing block  34  for cooperation with the ejection mechanism formed in the slide  14 . 
     The unitary sear housing block  34  may be manufactured using standard methods, such as machining or molding, in which case the slide rails are integrally formed as part of the housing  34 . Alternatively, the housing  34  may be assembled from various subcomponents attached together using standard means such as welding, adhesives, or fasteners. The housing  34  may be made of various materials, but will typically be composed of a light, high-strength metal or metal alloy. 
     It is envisioned that the sear housing block may be manufactured by over molding a detailed stamping with polymer. 
       FIG. 6  schematically illustrates the manner in which the sear housing block  34  and trigger mechanism housing  32  are attached to the frame  12 . As indicated, unitary sear housing block  34  and trigger mechanism housing  32  are configured for “drop in” insertion into the frame  12 . The frame includes a forward receptacle  84  and a rear receptacle  86 . The forward receptacle  84  is dimensioned to securely receive the trigger mechanism housing  32  and the rear receptacle  86  is dimensioned to securely receive the sear housing block  34 . 
     The receptacles  84 ,  86  are interior, upwardly open compartments or receptacles integrally formed as part of the frame  12  during manufacturing, and are complementary in shape to trigger mechanism housing  32  and the housing  34 , respectively. Once inserted into the receptacle  86 , the housing  34  is attached to the frame  12  using adhesives, welds, press or friction fit, or pins or the like (not shown). Optimally, the unitary sear housing block  34  is pinned into the frame  12  by a frame pin inserted through a frame locating hole  87 . 
     Additionally, the receptacle  86  is provided with angled or vertically oriented rails (not shown) for engagement into grooves or channels  90  formed in the sides of the unitary sear housing block  34  (see  FIGS. 3-5 ), for purposes of easily aligning the unitary sear housing block  34  with respect to the receptacle and frame for assembly. Notably, the frame locating hole  87  and the locating grooves  90  cooperate to accurately position the rear slide rails  80 ,  82 . Likewise, a hole  92 , for receiving the sear pin  51 , is formed in the body portion of the sear housing block  34  to ensure accurate and precise positioning of a pivotable sear with respect to the firing mechanism and with reference to the frame  12 . As the rear slide rails  80 ,  82  also position the striker  42  with reference to the frame  12 , the frame locating hole  87  and the locating grooves  90  work in tandem with the hole  92  and pin  51  to provide for accurate assembly of a functional firing mechanism at reduced cost when compared to prior modes of locating a sear within a firearm frame. Importantly, the frame locating hole  87 , slide rails  80 ,  82 , locating grooves  90  and sear position hole  92  ensure proper alignment of the sear mechanism with respect to the firing mechanism (striker), i.e., sear to striker height. 
     Once inserted into and attached to the frame  12 , the rear slider rails  80 ,  82  of the unitary sear housing block  34  lie in operative alignment with lead rails  88  (see  FIGS. 1-2 ) on either side of the fore/barrel end of the frame  12 , for further guidance of the slide  14 . In particular, the rails  80 ,  82 ,  88  extend along the underside of the slide  14  in the longitudinal direction to allow for cycling of the slide  14  between forward (battery) and rearward (retired) positions. Also, the trigger bar  54  is connected to the sear assembly  46 . Importantly, by incorporating the rails  80 ,  82  into the sear housing block  34 , any assembly variances between the sear housing block and the slide rails is eliminated, thus lowering any seen manufacturing and assembly differences. 
     In addition, as will be readily appreciated, by incorporating the ejector  103  into the sear housing block  34  as discussed above, total part components for the entire firearm is lowered, this making for a more consistent part assembly while lowering the overall cost of the firearm as a whole. 
     With the sear housing block  34  provided as a separate, modular component for attachment to the frame  12 , it is no longer necessary to machine or otherwise form the various component features of the housing  34  as part of the frame  12  during the manufacturing process. Accordingly, the overall design and manufacturing process is rendered more efficient, more flexible (e.g., the possibility of different configurations and I or different materials for the frame  12  and housing  34 ), and with less potential waste from manufacturing errors. Additionally, because the trigger and sear mechanism subcomponents can be attached to the housings prior to attaching the housings to the frame, the assembly process is simplified. 
     As should be appreciated, the receptacle  86  and unitary sear housing block  34  may be characterized as “modular housing means” cooperative with the frame  12  for removably supporting one or more operational components of the firearm (e.g., the housings support the operational components and can be inserted into and removed from the receptacles) and for supporting the slide  14  in a reciprocating manner. 
     An additional embodiment of the present invention may be characterized as a modular firearm system having one or more firearm frames  12  and one or more separate housing  34 , for holding, supporting, and/or guiding portions of a firearm operational mechanism. Each frame  12  has one or more receptacles for receiving the housings. The frames and housings are interchangeable, meaning that each frame accommodates all or some of the housings. Some of the receptacles may be configured to only accept one subset of the housings, e.g., if the frame has two receptacles, the first receptacle may be configured to accept one subgroup of housings and the second receptacle another subgroup of housings. 
     Although this invention has been shown and described with respect to the detailed embodiments thereof, it will be understood by those of skill in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed in the above detailed description, but that the invention will include all embodiments falling within the scope of the above description.