US2453747A

US2453747A - Shotgun choke

Info

Publication number: US2453747A
Application number: US783285A
Authority: US
Inventors: James E A Egleson
Original assignee: Individual
Current assignee: Individual
Priority date: 1947-10-31
Filing date: 1947-10-31
Publication date: 1948-11-16
Anticipated expiration: 1965-11-16

Description

NOV. 16, 1948. EGLESQN 2,453,747

- SHOTGUN CHOKE Filed on. 31, 1947 2 Sheets-Shet 1 IQTTUPA Z'VS Nov. 16, 1948. E, A, EGLESON 2,453,747

SHOTGUN CHOKE Filed 001;. 31, 1947 2 Sheets-Sheet 2 IIVVENTOR; WdlW BY Patented Nov. 16, 1948 i Sim 1 l This invention relates to gun chokes.

The general object of the invention is to provide a new and improved gun choke for shotguns arranged to be operated by the force of the expanding gases of combustion oi the powder to. effect automatically 9. choking action upon the muzzle of the gun so that, one shell having been fired, the muzzle will have been constricted tor the purpose of concentrating the shot pattern upon the firing of another shell.

A special object of the invention is to provide such a gun choke which may be attached to the muzzle of a shotgun barrel and may be manually adjusted so as to provide. an unchoked effective muzzle, and at the same time is operable so that upon the firing of a. shell the force'of the expanding gases of combustion of the powder will operate to effect a predetermined choking action upon the effective muzzle. Further, the invention contemplates such a gun choke which, attached to the muzzle of a shotgun, may be manually adjusted to choke the effective muzzle in a selected degree, and in which, upon the firing of a shell, the gases may be utilized to effect an additional, and predetermined, choking action upon the effective muzzle.

Another object is to provide apparatus which may be attached to a manuallymperable gun choke, said apparatus being arranged to be operated by the force of the expanding gases of combustion of the powder to effect choking action of the gun choke.-

Another object is to provide means whereby the force of the expanding gases of combustion of the powder of a fired shotgun shell may be utilized to effect a rotary motion of a rotatable member of a gun choke relatively to a split muzzle extension so as to constrict the elements of the split muzzle extension, and thereby vary the orifice through which the shot emerge.

Also, in general, the invention contemplates an improved automatic gun choke arranged to be operated by the force of the expanding gases of combustion of the powder of a fired shotgun shell so as to effect a. construction of the muzzle of the .gun immediately following the emergence of the .shot from each of a plurality of fired shells, so that the shot patterns of the fired shells successively decrease in diameter; and so that, in rapid firing, as, for example, in shooting at a withdrawing target, the pattern diameter decreases automatically as shells are fired, thereby compensating for the increasing distance between the muzzle and the target.v Further, the invention contemplatesthe provision ofmeanswhereby the 14 Claims. (Cl. 42- 79) delay incident to manual choking-tot themuzzle may be avoided in rapid. firing of ashotgun.

These and other objects willbe more-fully -understood from the following description and from thedrawings in which I I Fig. 1 is a sideview of a gun choke embodying the invention; r

. Fig. 2 is a section taken approximately onthe line 22 of Fig. 1;

Fig. 3 is a front view of the gun choke of Fig.- i; Fig. ,4 is a section taken on the line 4-4 ofFig.

FigsQS and 6 are details of means provided on the gunchoke of Fig. 1 for predetermining the v degree of choke to be automatically eflfected;

Fig. 7 is an axial section similar to Fig. 2 but on a slightly larger scale of a modified embodiment of the invention; and 1 Fig. sis an axial section similar to Fig. '7 0! another modification of the invention. A

The embodiment ofthe invention illustrated in (Figs. 1 to 6, inclusive, is a complete automatic gun choke arranged to be applied to the muzzle of a shotgun; r

Figs. 1 and 2 show the forward end of a shotgun barrel I. In- Fig. 2 the actual muzzle of the barrel is designated as 2. l The outside of the muzzle end of the barrel is threaded, and the sleeve 3 is internally threaded at 4 for engaging the threaded end of the barrel I so that itmay be attached to the muzzle end of the gun barrel. A split muzzle extension 3a of the gun barrel has its forward end tapered externally at 5, the tapered portion being split, parallel to the axis of the sleeve, by a plurality of slots 6 to provide a plurality of oonstrictable .fingers I (see also Fig. 4). The muzzle extension 311. is shown as a separate member with its rearward end externally threaded for engagement with the internal threads of the portion of the sleeve 3 that extends beyond the muzzle 2 for holding the gun barrel muzzle and muzzle extension in a butting relation as shown.

internally machined, The sleeve 3' is externally threaded at 8; and mounted thereon is a second sleeve 9, having internal threads at its rear end so that it may be adjustably positioned upon sleeve 3. The sleeve!) is internally tapered and constricted toward its forward end to formra conical cam III which operates to constrict the fingers I accordingly as the sleeve 9 is progressively threaded upon sleeve 3 The sleeve '9 is seen to be an annular member that is internally threaded for rotation relative to the split muzzle assays? 3 extension to and that is arranged to constrict the split muzzle extension when rotated.

The forward -end of sleeve 9 is externally threaded at I I and mounted thereon is the annular chamber member I! having internal threads at its rear end whereby it may betightly fitted upon the sleeve 9 so as to form what is in eifect an integral projection of the sleeve! extending beyond the mouth of the mumle extension la. Boththe inside and outside of the chamber member I! are constricted abruptly near the forward end to form the exit tube It, the internal diameter of which provides proximate clearance for the shot pattern when the split muzzle extension is unconstricted. Preferably, the internal diameter of the exit tube I9 is approximately equal to the internal diameter of the unchoked muzzle while being slightly greater in diameter so that the widest shot pattern will clear without interference. For example, if the internal diameter of the unchoked muzzle is .730 inch plus or minus .005 inch, the internal diameter of the exit tube I! may advantageously be .775 inch. The lntemal diameter of the intermediate portion of the chamber member I! is greater than the internal diameter of the exit tube l9 so that a chamber I4 is provided rearward of exit tube. The cylindrical wall of the chamber member i2 is provided with a plurality of angularly spaced longitudinally extending slots i5. Each such slot passes through the wall, not radially, but at an angle, as shown in Fig. 4, thereby ell'ectlvely converting the remaining and intervening strips ii of the wall into vanes having deflecting surfaces adapted to impart torque to the chamber member tending to rotate it in a clockwise direction (Fig. 4) under the influence of expanding gas passing outwardly through the slots IS. A plurality of relatively small, angularly spaced holes I! are provided in the shoulder of chamber member I: which is 4 v v lng. when the crosshead has been dropped into any of the slots I! it is apparent that the sleeve 9 cannot be advanced upon sleeve. 9 more than that distance corresponding to the rotary motion of sleeve 9 suiiicient to bring the lug 2| into contact with the crosshead of key 29. as shown in Figs. 1 and 5. The key :0, therefore, can be utilized as a stop to arrest the rotary motion of the sleeve 9 at a predetermined position which is controlled depending upon the indexing slot in which the crosshead of the key 29 is inserted. Whichever indexing slot the crosshead of the key so is inserted in. the sleeve 9 may be manually rotated in counterclockwise direction nearly one full turn (380) to the position shown in Fig. 6. The pitch of the threads 9 relative to cam i9 is preferably proportioned so that counterclockwise rotation of sleeve 9 through the full extent permitted by the key 29 will permit in all cases the lingers of the muzzle extension to to assume their fully uneonstricted (improved cylinder) position relative to the gun. There may be any desired number of the index slots i9, as for example, seven as shown. It the crosshead of the key 20 is positioncd in the slot having the index number I, the key 29 may be used as a chock so as to prevent clockwise rotation of the sleeve 9 to effect any choking action. At the other extreme. when the crosshead of the key 20 is inserted in the slot indexed as number I, then the sleeve 9 can be rotated to constrict the muzzle extension to the full choke position. When the crosshead is in-- serted in any of the intermediate indexing slots, the rotation of the sleeve can be arrested at any intermediate choke as may be desired. When the key 20 is in any of the slots other than that numbered I, the sleeve 9 can be manually rotated clo kwise until the lug 2| contacts the crosshead of the key-29. Any degree of choke as determined a by the position of the key can be effected in this formed where this member is abruptly constricted near the forward end to form the exit tube i9, said holes communicating from the inside of chamber id to the exterior of the chamber member i2 and preferably having their axes. inclined as shown so as to impart torque to the chamber member 12 in the same direction (clockwise) as that imparted by the slots I! when the gun is fired. (See Figs. 2 and 3.)

On the rearward end of-the sleeve 9 there is proyided a shoulder l8 having on its forwardly disposed edge a series of angularly spaced slots f9. which are shown in Figs. 1, 5 and 6 to be indexed with indexing numerals. On the sleeve 9, forward of the shoulder I8, is a key 20 formed of a 'r-shaped strip of suitable mater! ll, preferably hard, resilient metal, curved flatwise to form a nearly complete hoop that slidably engages the sleeve 3. The crosshead of the T is shaped to be received on one side within any of the slots l9, and on the other side to be engaged by and to serve as a detent for a lug 2| provided on the rear end of sleeve 9. In order to permit adjustment or disassembly of the gun choke, the sleeve 9 may be rotated counterclockwise upon sleeve 9 until the crosshead of the key 20 can be moved into the slot 22 that is in the sleeve 9 alongside the lug 2| so that the crosshead will be out of contact with any of the slots l9 as shown in dotted lines in Fig. 6. With the crosshead of the key 29' moved to this position, the key may be rotated with the sleeve 9 around sleeve 3 until the crosshead is brought opposite any of the indexing slots l9, or, if desired, the sleeve 9 can be completely removed for disassembly and cleanway and firing of the gun will not effect any further choking action. However, if the sleeve 9 is rotated counterclockwise from any such position, the sleeve will be free to be rotated clockwise automatically upon firing of the gun until the rotary motion of the sleeve is arrested by the position of the keylll, and this action automatically constricts the muzzle extension 3a to a more fully choked position. The gun can, of course, then be immediately fired again with the choke in the more advanced position.

When the position of the sleeve 9 relative to the key 20 is such that advancing rotary motion may be assumed by the sleeve, the rotation of the sleeve 9 upon the firing of the gun to choke the muzzle extension 3a is caused by the expansion of the gases following the wedding and shot as they are discharged from the muzzle extension through the chamber member l2 and through the exit tube Id. The gases following the wadding and shot, of course, expand rapidly and escape through slots I! in the chamber II. This action is augmented by the momentary blocking of other avenues of escape as the wedding and shot pass through the exit tube l3. The rapidly expanding gases which violently escape through the slots l5 impart moments against the deflecting faces of the strips l6 that rotate the chambermember I2 and in turn the sleeve 9) in a clockwise direction. During the occurrence of this action, the gases escaping through the holes II impart a rearward reaction upon the chamber member l2 and upon the sleeve 9 that assists in eflecting the choking action effected by the rotation of the sleeve 9. When the holes I! likewise are formed (as shown) so that their axes are not parallel to the bore of the barrel, but at an angle, the gas which escapes through them imparts, in addition to a rearward moment,

' with theiraxes parallel to the bore of the barrel while still affording adequate torque to effect/the automatic choking action when the gun is fired. Whether the holes II have their axes parallel'to the barrel or at an angle thereto, they are regarded as longitudinally extending orifices.

Depending upon the friction and inertia of the parts of the choke mechanism, the torque impulse upon the. chamber member I2 is sufiicient to effect a full rotation of the sleeve 3 or only a fractional portion of a full revolution. For example, the

3 impulse imparted by the firing of the gun may be sufiicient to rotate the sleeve 9 through a half revolution, more or less. In such case, if the key is set in the full choke position and the sleeve is initially manually retracted to the unchoked (improved cylinder) position, the first shot will rotate the sleeve 9 to effect approximately half choke (modified choke), while the second shot will cause further rotation of the sleeve 3 to effect full choke, at which time a third shot may then be fired. In order to assist in the, manual setting of cylinder 3 at the improved cylinder position or at any intermediate setting, the lug 2| may be used as an indexing indicia relative to the indexing slots 19, although any other indexing indicia may be used as may be convenient.

In Fig. '7 another embodiment is shown which illustrates the application of this invention to the automatic operation of a gun choke adapted to be detachably secured to the muzzle of a shotgun. In this modification, the split muzzle extension is detachably secured to the gun barrel I as by the threaded engagementshown. The muzzle of the gun barrel is indicated at 2. The split muzzle extension 30 has constrictable fingers 3| and external tapers at 32 and 32a. The sleeve 33 provides the cam surfaces acting on the

external tapers

32 and 32a for progressively constricting the fingers 3| when the sleeve 33 is rotated under the influence of the threading 29. The device thus far described is adapted for use as a manually operated choke. According to this invention, the choke is made automatically operable by the attachment to the sleeve 33 of the chamber member 34 as by the threaded engagement 35.

The chamber member 34 corresponds to the chamber member l2 shown in Figs. 1 to 6 and the slots 15, the vane-like wall strips IS, the holes l1 and the exit tube l3 correspond to the like-numbered elements of chamber member l2. The action of the vanes in the chamber member 34 in effecting rotary motion of the chamber and sleeve 33 to effect an automatic choking of the split muzzle extension when the gun is fired is similar to that previously described in connection with the embodiment shown in Figs. '1 to 6. In this embodiment there is no stop means for arresting the rotation of thesleeve 33 and reliance is placedon the friction and inertia of the rotatable parts, as, for example, so that the torque impulse tending to rotate the sleeve 33 upon the firing of the gun will afford half of a complete rotation, more or less, of the sleeve. However, if desired, a stop mechanism may be employed, as, for example, a stop mechanism such as that shown for purposes of lllustra tion in Figs. 1 to 6. However, it is not essential to employ a stop device, and in certain cases omission of the stop mechanism may be advantageous and 33.

in permitting successively increased choke increments upon successive shots fired. Of course, conventional indexing indicia may be employed to indicate therelative positions of the sleeve 33 In Fig. 8, another embodiment of this invention is shown wherein the split muzzle extension is an integral part of the muzzle end of the shotgun barrel. The muzzle extension comprises the constrictable fingers 36 which are externallytapered,

the taper being indicated at 31. The sleeve 39 by the threads 38 is rotatably secured to the gun barrel just back of the inner ends of the fingers 36 so that by rotation of the sleeve 39 the internal taper of the outer end of sleeve 39 will act to choke the muzzle of the gun barrel. The chamber member 40 is similar to the chamber member 139i the embodiment shown in Figs. 1 to 6 including'the slots IS, the vanes IS, the holes I! and the exit tube l3. As in the case of the embodiment shown in Fig. '7, a stop device to arrest the rotation of the sleeve 33 may be employed if desired and appropriate indexing indicia may be employed.

While this invention has been described in connection with the specific embodiments shown, it is apparent that the principles of this invention permit other modifications. Thus, the slots in the chamber member may be of other configurations as by making them spiral or of other lengths, and it is apparent that any openings laterally adjacent the mouth of the split muzzle extension can be employed which provide deflecting surfaces for imparting torque to the sleeve for choking the split muzzle extension of the gun barrel. The holes I! are not essential and may be omitted. The exit tube l3 may also be omitted but augments the torque. When the exit tube I3 is employed and is preferably about inch in length, the torque action has been found to be most efiective. More generally, the scope of the invention whereby a shotgun choke is automatically operated by utilizing the expanding gases discharged from the shotgun barrel to supply torque for rotating a number to constrict the choke is to be governed by the language of the following claims.

' rotatable sleeve member therefor constructed and arranged to constrict said split muzzle extension upon rotation thereof relatively to said split muzzle extension, and a plurality of inclined vane members carried by said sleeve member laterally adjacent the mouth of saidsplit muzzle extension effective to rotate said sleeve member to constrict said split muzzle extension responsive to expansion of gases discharged from said split muzzle extension. 3. Choke mechanism for a shotgun accordin to claim 2 which comprises adjustable stop means adapted to arrest rotation of said sleeve member relative to said split muzzle extension.

4. The combination with a gun choke mechanism comprising a split muzzle extension and an annular member constructed and arranged to constrict the former when rotated.'oi an annular projection of said annular member extending beyond the mouth 01 said split muzzle tension, said projection havinga plurality of deflecting surfaces therein arranged to deflect expanding gas discharged from said split muzzle extension to impart rotational torque eflective-to constrict said split muzzle extension.

5. The combination according to claim 4 comprising a detent adapted to be selectively fixed in any one oi a plurality of angular positions relative to said split muzzle extension and a lug carried by said annular member, the Iormer in the path of .the latter for arresting rotation of said annular member at a predetermined angular position relative to said extension.

6. The combination with a gun choke mechani'sm comprising asplit muzzle extension and an annular member internally threaded for rotation relative to said extension in threaded engagement therewith and constructed and arranged to constrict said extension when rotated, oi means rigidly carried by said annular member arranged to be rotated in the presence of expanding gas discharged from said split muzzle extension, said means comprising an annular projection of said annular member extending beyond the mouth of said split muzzle extension that has its forward end constricted to a diameter approximately equal to but slightly larger than that of said split muzzle extension when the latter is not constricted, and that has in the wall thereof a plurality of openings through which expanding gas may pass, said openings'beirig so shaped as to deflect the path of expanding gas passing therethrough to impart rotational ,torque to said annular projection.

'7. The combination of claim 6 wherein said annular projection has a plurality of longitudinally extending orifices surrounding the constricted forward end thereof through which orifices expanding gas may pass for the purpose of imposing recoil directly on said annular projection.

8. The combination with a gun choke mecha-' nism comprising an externally tapered split muzzle extension and an internally tapered annular member internally threaded for rotation relative to said extension in threaded engagement therewith and constructed and arranged to constrict said extension when rotated, of a cylindrical chamber member rotatable integrally with said annular member having its internal diameter larger than the internal diameter of said split muzzle extension when unconstricted and having its forward end constricted to provide a bore of substantial length coaxial with said split muzzle extension and of internal diameter approximately equal to but slightly larger than that of the split muzzle extension when unccnstrlcted, said cylindrical chamber member being provided with a plurality of slots presenting longitudinally extending deflecting surfaces for deflecting expanding gas to impart rotational movement to said cylindrical chamber member for constricting said split muzzle extension.

9. The combination according to claim 8 where- I in said cylindrical chamber member has a plurality oi longitudinally extending orifices surrounding the constricted forward end of said chamber member whose axes are inclined to the axis oi said chamber member at an angle such that expanding gas passing therethrough imparts torque for imparting rotational movement to said chamber member in the same direction as that eii'ected by said deflecting surfaces provided by said slots and also imposes recoil directly on said said gun barrel and the internal diameter of which provides proximate clearance for the widest shot pattern passing therethrough, said cylindri- 1 cal member having openings in the side well thereof arranged to deflect gas escaping therethrough from said gun barrel after the firing of a shell within said barrel so as to rotate said cylindrical member and said cam and thereby constrict said split muzzle extension.

11. The combination with a shotgun having a 'barrelwith an externally tapered constrictable split muzzle, of a sleeve threaded'on said muzzle and internally tapered to constrict said muzzle when rotated, said sleeve extending beyond said muzzle to provide an expanded chamber having an orifice which is coaxial with said gun barrel and the internal diameter of which provides proximate clearance for the widest shot pattern passing therethrough, said sleeve having openings in the wall thereof arranged to deflect gas escaping therethrough from said gun barrel following the firing of a shell within said barrel for the purpose of effecting a rotary motion in said sleeve to constrict said split muzzle. I

12. Choke mechanism for a shotgun comprising a constrictable split-muzzle extension, an exit tube spaced from the mouth of said split muzzle extension in line therewith whose internal diameter provides proximate clearance for the shot pattern when the split muzzle extension is not constricted, a rotatable vane carrying member laterally apertured to provide vanes between the mouth of said split muzzle extension and said exit tube that are laterally adjacent the mouth of said muzzle extension and that are adapted to deflect expanding gases discharged from said split muzzle extension to impart rotational torque to said vane carrying member, and means for constricting said split muzzle extension responsive to rotation of said vane carrying member upon discharge of expanding gases from the mouth of said split muzzle extension.

13. Choke mechanism for a shotgun according to. claim 12 wherein said vane carrying member has a side wall of annular cross-section that is coaxial with said exit tube and is of larger internal diameter than said exit tube immediately adjacent the inner end of said exit tube for providing an obstruction of gases discharged from said split muzzle extension, the vanes carried by said -vane carrying member being provided by a plurality of longitudinally extending slots in said side wall of said annular member inclined substantially in a common direction from radii extending from the axis of said vane carrying member.

14. A shotgun choke mechanism comprising a constrictable gun muzzle extension, a rotatable member cooperating with said constrictable gun muzzle extension and constructed and arranged for constricting said gun muzzle extension upon rotation of said member relative to said gun muzzle'extension. and an extension carried by said member and having exhaust vents presenting laterally inclined deflecting surfaces adjacent the mouth of said constrictable gun muzzle extension and so directed as to produce rotation of said member to choke said gun muzzle extension in response to passage of the expanding explosion gases discharged from said gun muzzle extension therethrough.

. JAMES E. 'A. EGLESON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 811,595 Taylor Feb. 6, 1906 2,398,298 Finlay et a1 Apr. 9, 1946