Two piece upper receiver for firearms

Abstract

A two piece upper receiver for a firearm including a first piece having a front end, a rear end, a top, and a bottom, the first piece constructed to operatively carry a bolt carrier and bolt, and to have a barrel coupled to the front end. The bottom is constructed to have a lower receiver coupled thereto. The first piece includes a backbone extending along the top between the front end and the rear end, the backbone having upwardly directed indexing surfaces. A second piece overlies the backbone and includes mating surfaces engaging the indexing surfaces, aligning the second piece with the first piece. A receiving structure is opposite the mating surfaces for receiving accessory devices mounted thereon. Fasteners fixedly attach the second piece to the first piece to form a complete upper receiver.

1 . A two piece upper receiver for a firearm including a barrel, the two piece upper receiver comprising:
 a first piece having a front end, a rear end, a top, and a bottom, the first piece constructed to operatively carry a bolt carrier and bolt, and to have the barrel coupled to the front end, the bottom constructed to have a lower receiver coupled thereto, the first piece including a backbone extending along the top between the front end and the rear end, the back bone having upwardly directed indexing surfaces;   a second piece overlying the backbone of the first piece and including mating surfaces engaging the indexing surfaces aligning the second piece with the first piece, and a receiving structure opposite the mating surfaces for receiving accessory devices mounted thereon; and   fasteners fixedly attaching the second piece to the first piece to form a complete upper receiver.   
     
     
         2 . The two piece upper receiver of  claim 1  wherein the front end, the rear end, the top, the bottom and the backbone all form a single, continuous, one-piece, first piece. 
     
     
         3 . The two piece upper receiver of  claim 1  wherein the backbone has a length extending substantially from the front end to the rear end, and having a continuous thickness along the length thereof providing rigidity and strength to the first piece. 
     
     
         4 . The two piece upper receiver of  claim 3  wherein the continuous thickness of the backbone is uncompromised by transversely thinning discontinuities. 
     
     
         5 . The two piece upper receiver of  claim 1  wherein the backbone defines the indexing surfaces which are upwardly directed and angularly opposed. 
     
     
         6 . The two piece upper receiver of  claim 5  wherein each of the angularly opposed indexing surfaces lies on a separate plane, which planes intersect at a ninety degree angle. 
     
     
         7 . The two piece upper receiver of  claim 1  wherein only the mating surfaces of the second piece engage the backbone of the first piece. 
     
     
         8 . The two piece upper receiver of  claim 1  wherein the second piece has an inner surface and an outer surface, the second piece overlying and partially enclosing the backbone of the first piece. 
     
     
         9 . The two piece upper receiver of  claim 8  wherein the inner surface defines the mating surfaces, the mating surfaces are downwardly directed and angularly opposed and the outer surface includes the receiving structure for receiving accessory devices mounted thereon, only the mating surfaces engaging the backbone at the indexing surfaces, with gaps defined between remaining portions of the inner surface and the backbone. 
     
     
         10 . A two piece upper receiver for a firearm including a barrel, the two piece upper receiver comprising:
 a first piece having a front end, a rear end, a top, and a bottom, the first piece constructed to operatively carry a bolt carrier and bolt, and to have the barrel coupled to the front end, the bottom constructed to have a lower receiver coupled thereto, the first piece including an integrally formed backbone extending along the top between the front end and the rear end, the back bone defining upwardly directed, angularly opposed indexing surfaces;   a second piece having an inner surface and an outer surface, the second piece overlying and partially enclosing the backbone of the first piece, the inner surface including downwardly directed, angularly opposed mating surfaces engaging the indexing surfaces to align the second piece with the first piece, and the outer surface including a receiving structure for receiving accessory devices mounted thereon; and   fasteners fixedly attaching the second piece to the first piece to form a complete upper receiver.   
     
     
         11 . The two piece upper receiver of  claim 10  wherein the backbone has a length extending substantially from the front end to the rear end, and having a continuous thickness along the length thereof providing rigidity and strength to the first piece. 
     
     
         12 . The two piece upper receiver of  claim 10  wherein each of the angularly opposed indexing surfaces lies on a separate plane, which planes intersect at a ninety degree angle. 
     
     
         13 . The two piece upper receiver of  claim 10  wherein only the mating surfaces of the second piece engage the backbone of the first piece. 
     
     
         14 . The two piece upper receiver of  claim 10  wherein only the mating surfaces engage the backbone at the indexing surfaces, with gaps defined between remaining portions of the inner surface and the backbone. 
     
     
         15 . A firearm comprising:
 a barrel;   a lower receiver; and   a two piece upper receiver including a first piece having a front end, a rear end, a top, and a bottom, the first piece carrying a bolt carrier and bolt and the barrel coupled to the front end, the lower receiver coupled to the bottom of the first piece of the two piece upper receiver, the first piece including, as an integral part, a backbone extending along the top between the front end and the rear end, the back bone having upwardly directed indexing surfaces, a second piece overlying the backbone of the first piece and including downwardly directed mating surfaces engaging the indexing surfaces, the engaged mating surfaces and indexing surfaces aligning the second piece with the first piece, and a receiving structure opposite the mating surfaces for receiving accessory devices mounted thereon, and fasteners fixedly attaching the second piece to the first piece to form a complete upper receiver.   
     
     
         16 . The firearm of  claim 15  wherein the backbone has a length extending substantially from the front end to the rear end, and having a continuous thickness along the length thereof providing rigidity and strength to the first piece. 
     
     
         17 . The firearm of  claim 15  wherein the backbone defines indexing surfaces which are upwardly directed and angularly opposed. 
     
     
         18 . The firearm the  claim 17  wherein each of the angularly opposed indexing surfaces lies on a separate plane, which planes intersect at a ninety degree angle. 
     
     
         19 . The firearm of  claim 15  wherein only the mating surfaces of the second piece engage the backbone of the first piece. 
     
     
         20 . The firearm of  claim 15  wherein the second piece has an inner surface and an outer surface, the second piece overlying and partially enclosing the backbone of the first piece, only the mating surfaces engage the backbone at the indexing surfaces, with gaps defined between remaining portions of the inner surface and the backbone.