US 3171226: "FIREARM VENTILATED SIGHT RIB WITH April DOVETAIL KEY (OCR)"



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Patent Overview

Patent Title: FIREARM VENTILATED SIGHT RIB WITH April DOVETAIL KEY (OCR)
Patent Number: 3171226 Filing Date: Jun 12, 1963
Application Number: Issue Date: Mar 02, 1965
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Description

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March 21 1965 H. A. INTO 39l7lp226 FIREARM VENTILATED SIGHT RIB WITH A DOVETAIL KEY Filed June 12, 1963 IA- INVLWTOP- HENI?K A. flVTO BY ATRORNEY


United States Patetit Office 3,171@226 3,171,226 FIREARM VENTILATED SIGIIT RIB WITH A DOVETAIL KEY Henry A. Into, Waliingford, Conn., assigiior to 01'm I; Mathieson Chemical Corporati(;n, a corporation of , Virginia Filed June 12, 1963, Ser. No. 287,316 6 Claims. (Cl. 42-76) This invention relates to siaht ribs for shotguns and the 10 like. This invention more specifically relates to a floatin.- ventilated sight rib adapted to be mounted on a shotgun barrel or the like in a simple aiid economical manner. Ventilated sight ribs for shotguns and the lilre are 15 well known in the art. The object of pro-viding a venti- lated sight rib is to overcome the delrimental effects on sighting a shotgun caused by heat waves rising from the heated barrel and interfering with the line of sight. A ventilated rib interrupts the heat waves from the barrel 20 and is itself maintained cool by air circulatin.- arotind the rib. One of the problenis encountered in securing a venti- lated si.-ht rib to a gun barrel arises due to the unequal heating of the barrel and the rib and therefore the dif- 25 ferent degrees of expansion of these elements. If the rib is rigidly secured to the barrel along its length, there is a tendency for the rib to stretch due to unequal heat- ing and cause a curvature itself detrimental to the proper si.-hting of the firearm. It is therefore desirable that the 20 sight rib be moulited on the barrel in s,,ich a manner that the sight rib and the barrel can expand independentiy with no adverse effect such as mentioned above. To provide for such a mounting arrangement, it is desirable that the rib be rigidly attached to the gun barrel at -only a single 35 point and slidably carried by the barrel along the rest of its length. Prior art devices are knolvn in which such a single point of rigid attachment is used to n-iount a sight rib on a gun barrel. The prior art structures - normally provide a pin or screw which is passed through the rib 40 and threaded into one of the moiinting posts for the rib which is in turn rigidly attached to the barrel. Such an arrangement is shown in U.S. Patent No. 2,620,583 issued to Simmons. This arrangement introduces another prob- lem since the diameter of the pin which can be used in 4,5 such an arrangement is limited by practical consider- ations. There is therefore a tendency for the pin to be sheared off due to the mass of the sight rib being ac- celerated by the recoil of the firearm as it is fired. TO 50 overcome these deficiencies, a depending lug has been rigidly secured to the sight rib and made to interlock be- hind another lug rigidly attached to the barrel to absorb the recoil shock. Such an arrangement is shown in U.S. Patent No. 2,669,052 issued to Simmons. While this provides a satisfactory arrangement for relieving shear 55 stresses on the mounting pin, it introduces additional ex- pense in both the fabricating and mounting operation. It is a feature of this invention to provide a sight rib and mounting for shotguns or the like which overcomes the deficiencies of the prior art and which is simple and 60 economical to fabricate and install. According to this invention, a sight rib is provided with a longitudinal female groove of dovetail cross sec- tion extending along its entire length. The female dove- tail groove is of equal cross section throughout its entire 65 len,-th to facilitate manufacturing and to reduce cost. A plurality of support posts havina male projections of dovetail cross section are secured to the gun barrel adapted to interlock with the female dovetlail groove on the sight rib which is slid onto the posts. The support 70 posts mount the rib in spaced relation relative to the bar- rel. Intermediate the ends of the barrel, an anchor post Patented Mar. 2, 1965 2 is rigidly attached to the barrel. The anchor post includes a pair of integral male dovetail projections separated by a female recess of dovetail cross section extending transversely of the anchor post. The pair of male dovetail projections on the anchor post engage and slipport the sight rib in the same manner as the stipport posts referred to above. The sight rib is further provided with a transverse female recess of dovetail cross section which is directly aligned iwth the transverse recess in the anchor post when the sight rib is in proper mounted position on the barrel. A male key of double dovetail cross section is then inserted in the aligned transverse recesses in the ir@ounting post and sight rib to lock the sight rib against longitudinal movement relative to the barrel. The key has sufficient bearing and cross sectional area to absorb all impact forces on the sight rib which occur when the glin is fired. These forces are distributed uniformly through the relatively wide bearing areas of the key. A pin Nvhich may be in tl-.e form of a middle sight interlocks the sight rib when the key to prevent inadvertent transverse movement of the key relative to the sight rib. The pin is passed through the sight rib and secured in the key by screw threads or the like. It is readily apparent that there are no forces transmitted to this pin which would have a tendency to shear the pin. All impact forces are transmitted to the k--y itself. Another advantage of this system is that the simple dovetail cross section in all interlocking elements is readily machinable with great accuracy. It is therefore possible to obtain a tight mating fit of all parts in the mounting system, thereby minimizin.- the shear forces caiised by acn-eleration of the rib during recoil. This invention will now be described in detail with re_ference to the accompanying drawings in which: FIGURE I is a side view showing the sight rib of this invention mounted on the barrel of a firearm. FIGURE 2 is a perspective view showing the details of the rib prior to assembly. FIGURE 3 is a perspective view showing the details of the rib in assembled condition on a gun barrel. Referring nonv to the drawings, a barrel I is shown mounted on the receiver 2 of a firearm. A plurality of support posts 3 are rigidly secured to the barrel by soldering, brazing or other equivalent means. Each of the support posts is provided with an integral male projection 4 of dovetal cross section as clearly seen in FIGURE 2. Mounted on the barrel 1 intermediate the ends thereof is an anchor post generally indicated 5. The anchor post 5 is preferably provided with a pair of male projections 6 and 7 of dovetail cross sectional configuration. Formed in the anchor post intermediate the projections 6 and 7 is a female recess 8 having a dovetail cross sectional configuration. A sight rib 9 is slidably mounted on said support posts 3 aid anchor post 5. Sight rib 9 is provided with a female groove 10 of dovetail cross section which extends the entire len.ol,h of said rib. Female dovetail groove 10 interlocks with r@iale dovetail projections 6 and 7 on anchor post 5 and projections 4 on support posts 3 to mount said rib for longitudinal sliding n-iovement relative to the barrel 1. A transverse female recess 11 is formed in the si@-ht rib 9 which is vertically aligned with transverse recess 8 in the anchor post 5 when the sight rib 9 is in proper mounted position on the barrel 1. Recess 11 also has a dovetail cross section so that when recesses 8 and 11 are aligned, a combined female opening is formed in the sight rib and anchor post which is essentially of double dovetail cross section as clearly seen in FIGURE 3. Sight rib 9 is locked against longitudinal movement relative to barrel I at a single point so that the remainder of the rib is slidably carried by the barrel along the re-


rnainder o@f its length. This arrangement allows the rib to expand @,and contract at a different rate than the barrel as the bariel is heated during firing of the firearin. To lock the rib.. 9 agaidst longitudinal movement relative to the barrel, a key 12 of double dovetail cross sectional confl.-uration i-S inserted into the opening formed by transverse recesses 8 and 11. Key 12, as is apparent from the drawings, prgvides a relatively large bearing area to transmit the forces of recoil uniformly from the rib to the barrel as tle firearm is fired. In order to securely hold key 12 in pas:@tion in the transverse recesses 8 and 11, a pin 13 is Dassed through an opening 14 in rib 9 and screw-threadidly engaged iii opening 15 in key i[2. Pin 13 may be an ordinary screw or it may take the form of a middle sight as shown in the drawings. It is readily apparent that there are no shear forces acting on pin 13 which has the primary fu-@ict@oii of retainin@ male key 12 iii the female recesses 'a and 11. While the transverse recesses 8 and 11 are preferably formed of dovetail cross sectional configuration and the key 12 has a corresponding coiifiguration; it is apparetit thall these configurations could be made ac-@ierally rect-,tn-.Ular and perfonn the function of locking the rib against longitudinal movement. The principal advantage of the dovetail configuration, however, is that it ftinctions to lock the rib at th-- point of rigid connection to the barrel against movement vertically aw,,)y from the barrel as well as holding against longitudinal movemeiit of the rib. This consideration is even more significant if it is found desirable to eliminate one or both of the projections 6 and 7 from the anchor post. While this inventio-n has been described in detail with reference to a preferred embodiment illustrated in the drawings, all variations in design and structural detail are contemplated which are within the spirit and scope of the kdpended claims. I claim: 1. In a firearm including a barrel, a plurality of support posts rigidly secured to said barrel at longitudinally spaced intervals, a sight rib mounted on said support posts for longl'tudinal slidable mov@-ment relative to sa'@d barrel, an anchor post rigidly secured to said barrel interrnediate the ends of said barrel, said anchor post having a first recess extending transversely of said barrel, a- corresponding second recess formed in said sight rib in aligned relationship with the recess in said alichor post and extending transversely of said barrel, a key mounted in said recesses to securely lock said sight rib against relative movement long,'@tudinally of said barrel, pin means extending through said sight rib and into said key to lock said key securely in said recesses, said key extending substantially across the width of said rib to provide a maximum bearin- surface to absorb longitudinal recoil forces transmitted from the barrel to said rib. 3,171,226 2. The firearm of clain-i I in which each of said support posts has formed integral therewith a projecting portion of dovetail cross section adapted to interlock with a groove of dovetail cross section which extends the entire length of said sight rib. 3. The firearm of claim 2 in which said anchor post includes a pair of projections of dovetail cross section adapted to interlock with said groove in said sight rib and in which sa-d firsc recess is forw-ed between said pair of 10 projectio-iis. 4. The firearni of claim 3 in which said first and second recesses are of dovetail cross s@-etion and said key has a do-Lible dovetail cross sectional configuration to interlock sa-'@d suppo@-t post and said si.-ht rib against vertical sepa- 15 ration. 5. The firearm of claim I in which said first and second recesses have a dovetail cross section and s,,iid key is of double dovetail cross section to sectirely lock said rib and said anchor post against vertical separation. 20 6. In comb-nation with a firearm hiving a barrel, a plurality of s- apport posts rigidly fixed to said barrel in longitudinally spaced relationsbip, an tipwardly extendi-@ig dovetail projection on each of said mountin@- posts, a sight rib muinted on said barrel, said si@ it rib having a 25 groove of dovetail cross section extending the entire length of said rib, said groove b-.iiig ad-,ipted to interlock with the dovetail projections on said mounting posts, an anchor post rigidly secured to said barrel intermediate the ends of said barrel, said anchor post includin@@ a pair of lon@-i- 30 tudinally spaced upwardly extending dovetail projections to interlock with said @roove on said rib, a first transverse recess formed in said anchor post between said pair of projections, a second transverse recess formed in said sight rib in align-@d relationship with said first t,-ansverse 3,5 recess in said an--hor post, said first and second recesses having a dovet-,Lil cross section, a k@-y mounted in said transverse recess-.s to lock said rib against longitudinal movement relative to said barrel, said key having a double dovetail cross section for insertion into said first 40 and second recesses, said key providipg a maximum bearin.- surface to absorb recoil forces transmitted from said barrel to said rib. References Cited by the Examiner 45 UNITED STATES PATENTS 1,323,149 11/19 Blizard ------------------ 42-1 2,496,854 2/50 Crank ------------------ 42-76 2,62G,583 12/52 Simmons --------------- 42-76 3,107,450 10/63 Snyder et al -------------- 42-76 50 FOREIGN PATENTS 146,533 12/03 Germany. BENJAMIN A. BORCHELT, Primary Exaininer.

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