Patent Publication Number: US-7216450-B2

Title: Frame assembly of handgun with different hardnesses

Description:
FIELD OF THE INVENTION 
   The present invention relates generally to handguns, and particularly to a handgun that includes a frame assembly having different hardnesses, e.g., a polymer frame assembly with some of the polymer being harder than other portions of the polymer. 
   BACKGROUND OF THE INVENTION 
   It has been common practice in the art of weapons to manufacture handguns and other firearms from different hard materials, such as different metals, with or without a combination of wood or hard plastics. This combination of materials has several advantages, such as saving money and time in production, reducing weight and other benefits. 
   Starting in the late 1970&#39;s, early 1980&#39;s, different handgun manufacturers like Glock, Steyr, Walther, H&amp;K, Taurus and others started producing firearms and mainly handguns from different hard polymers. In the prior art, polymer handguns are made of one single type of polymer, with all portions of the polymer body having the same basic hardness. 
   SUMMARY OF THE INVENTION 
   The present invention seeks to provide a handgun that includes a frame assembly having different hardnesses, as is described more in detail hereinbelow. 
   There is provided in accordance with an embodiment of the present invention a handgun including a one-piece frame assembly including a slide interface portion, a grip portion and a trigger guard, wherein the frame assembly includes at least two portions that have different hardnesses, and a firing assembly that includes a slide supported for reciprocal longitudinal sliding movement on the slide interface portion. For example, the slide interface portion (and the trigger guard) may be harder than the grip portion. The slide interface portion may be harder than the trigger guard. Front and rear structural members of the slide interface portion, which are located in areas subject to firing-related high stress, may be harder than other portions of the slide interface portion. 
   The one-piece frame assembly may be fabricated by injection molding a relatively high hardness polymer and the grip portion is formed by over-molding a softer material over the polymer. Alternatively, the one-piece frame assembly may be fabricated by multiple injection molding, wherein the slide interface portion is molded of a relatively high hardness polymer and the grip portion is molded of a softer material. As another alternative, the one-piece frame assembly may be fabricated by injection of a polymer that is cured and hardened to different levels of hardness such that the slide interface portion is harder than the grip portion. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be understood and appreciated more fully from the following detailed description taken in conjunction with the drawings in which: 
       FIG. 1  is a simplified exploded illustration of a handgun constructed and operative in accordance with an embodiment of the present invention; and 
       FIG. 2  is a simplified illustration of a method for constructing the handgun of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF EMBODIMENTS 
   Reference is now made to  FIG. 1 , which illustrates a handgun  10 , constructed and operative in accordance with an embodiment of the present invention. The illustrated handgun is based on an illustration found in U.S. Pat. No. 6,401,379, but this is merely for the sake of simplicity and clarity, and the present invention is in no way limited by this particular illustrated construction. 
   Handgun  10  may have a frame assembly  12  and a firing assembly that includes a slide  14 . Those skilled in the art will readily appreciate that only those parts of handgun  10  that are needed to explain the present invention are shown, but the firing assembly of handgun  10  in actuality may include many other parts, such as but not limited to, a barrel, a breech block, a trigger, a trigger bar, a sear, a striker, and various springs that are well known in the art and are therefore do not require detailed description and are omitted in the drawing for the sake of simplicity. 
   Briefly, slide  14  may have a laterally open ejection port  18 , and a front end segment  22 . An upper portion of the front end segment  22  may have an opening  28  for receiving the muzzle of the barrel (not shown) as is known in the art. A lower portion of the front end segment  22  may have a front pair  30  of oppositely disposed, first and second grooves  32  and  34  formed in an exterior surface  36 . The first and second grooves  32  and  34  may extend longitudinally the full length of the right and left sides of front end segment  22 . Slide  14  may be constructed of a high strength metal (e.g., alloy steel) as is well known in the art. 
   Slide  14  may be supported on frame assembly  12 , for reciprocal longitudinal sliding movement between battery and retired positions, by a pair of primary rails  116  (one of which is seen in  FIG. 1 ) which are disposed within grooves  32  and  34 , and secondary rails  112  and  114  which are disposed within a rear pair of grooves (not shown) of slide  14 . Right and left rail segments  102  and  104  may extend rearward from secondary rails  112  and  114 , respectively. A recoil spring assembly (not shown), which may include a recoil spring and a recoil spring guide (not shown), may act between the forward end of slide  14  and a forwardly facing surface on frame assembly  12  to bias slide  14  in a forward direction toward the battery position. 
   Frame assembly  12  may include a slide interface portion  40  that has front and rear portions  68  and  70 , respectively. The slide interface portion  40  may have an upwardly open channel  60  extending generally from one end to the other end of frame assembly  12 . The slide interface portion  40  is adapted to house the firing mechanism (not shown) of the firing assembly and cooperate with slide  14  to house the barrel (not shown). 
   The front and rear portions  68  and  70  may respectively include front and rear structural members  64  and  66 , located in an area of the slide interface portion  40  that is subject to firing-related high stress. 
   Frame assembly  12  may include a grip portion  42  that has a magazine well  44  for inserting therein a magazine (not shown). Grip portion  42  may have (integrally formed therewith) a front strap  62 , a back strap  58  and side panels  59 . The slide interface portion  40  may include magazine lips  120  and  122  for catching the upper end of the magazine. 
   Frame assembly  12  may further include a trigger guard  46 . 
   In accordance with an embodiment of the invention, frame assembly  12  includes at least two portions that have different hardnesses. For example, slide interface portion  40  may be harder than grip portion  42 . This may be accomplished by several methods, as is now explained with further reference to  FIG. 2 . 
   In one example, frame assembly  12  may have a unitary (one-piece) structure, e.g., fabricated by injection molding a high strength, heat and corrosion resistant polymer, which has a relatively high hardness, such as but not limited to, nylon 6/6 or commercially available polymer RTP 299H54780. Grip portion  42  may be formed by over-molding a softer material over the high strength polymer base. For example, in the over-molding process, a well known technique in the molding art, a soft TPE (ThermoPlastic Elastomer) may be molded over a base of a rigid material (e.g., nylon 6/6). In this example, grip portion  42  has two layers, wherein the outer layer is softer than the inner layer, thus providing a good hold and grip of handgun  10 . The slide interface portion  40  is made just of the hard polymer and is thus harder than grip portion  42 . 
   In another example, frame assembly  12  may have a unitary (one-piece) structure made by the process of double or multiple injection, a well known technique in the molding art. Double injection can inject two colors or two different materials (e.g., ABS and rubber, or nylon 6/6 and silicone rubber) in the same mold and process (multiple injection is the more general term and includes injecting two or more materials). It reduces costs by the use of a single operation. (See, for example, U.S. Pat. Nos. 4,701,292, 4,808,101 or 6,352,427). By using well known double or multiple injection techniques, slide interface portion  40  may be constructed of a harder polymer (e.g., injection molded of nylon 6/6) than grip portion  42  (e.g., injection molded of TPE). 
   In yet another example, frame assembly  12  may have a unitary (one-piece) structure made by single injection of a polymer that is cured and hardened to different levels of hardness such that slide interface portion  40  is harder than grip portion  42 . Alternatively, frame assembly  12  may have a unitary (one-piece) structure made by machining or casting a single metal or more than one metal, which may be heat-treated to different levels of hardness such that slide interface portion  40  is harder than grip portion  42 . For example, slide interface portion  40  may be surface hardened to a relatively high Rockwell C hardness while grip portion  42  may be annealed to be softer. 
   In all of the above examples, trigger guard  46  may be constructed together with slide interface portion  40 , and may thus be harder than grip portion  42 , too. Alternatively, trigger guard  46  may be constructed of another material with an intermediate hardness, less than that of slide interface portion  40  but more than that of grip portion  42 . 
   As another example, because the front and rear structural members  64  and  66  are located in areas subject to firing-related high stress, front and rear structural members  64  and  66  may be hardened or may be injection molded of higher hardness than grip portion  42  (or than other portions of slide interface portion  40 ). 
   It will be appreciated by persons skilled in the art that the present invention is not limited by what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of the features described hereinabove as well as modifications and variations thereof which would occur to a person of skill in the art upon reading the foregoing description and which are not in the prior art.