US 3161979 A
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"urn" United States Patent O M ce 3,161,979 ADJUSTABLE SHOTGUN CHOKE DEVICE Charles E. Lowe, West Hartford, Conn., assigner to Hartford Gun Choke Co., Inc., Newington, Conn., a corporation of Connecticut Filed Aug. 11, 1961, Ser. No. 130,905
2 Claims. (Cl. 42--79) The present invention relates to adjustable shotgun choke devices.
Among those owning semi-automatic or pump or slide action Shotguns, adjustable choke devices have been well accepted as they enable a single barrel shotgun to be quickly and easily adapted to meet the requirements of all types of shooting by varying the amount of choke. These devices are commonly provided with slots arranged and disposed so that they have the added advantage of functioning to reduce the recoil. It has been recognized that chokes affect shot patterns and the general objective of this invention is to provide shotgun choke devices that enable better shot patterns and shorter shot strings to be obtained with greater uniformity regardless 'of the choke setting.
In accordance with the invention, this objective is attained by providing a shotgun choke device including a tubular element attachable at one end to the muzzle of a shotgun barrel and having, at its other end, a plurality of forwardly disposed resilient choke lingers which are circumferentially spaced to provide intermediate slots. A sleeve is threaded on the element and has a forwardly and inwardly tapering shoulder engageable with the lingers as the sleeve is threaded on the elements and the shoulder is operative to force the ends of the ngers inwardly. The sleeve has a plurality of apertures overlying the slots in the element and operative, in any setting 'of the choke device, to vent the barrel rearwardly of but closelyadjacent the shoulder of the sleeve. Such venting, being in the choke area, results in improved patterns and shorter shot strings being uniformly attained regardless of the choke setting.
In the accompanying drawings, there are shown illustrative embodiments of the invention from which these and other of its objectives, novel features, and advantages will be readily apparent.
In the drawings:
FIGURE 1 is a side elevation of a choke device in accordance with the invention shown as installed on the muzzle of a shotgun barrel with the device adjusted for one position of use, i
FIGURES 2, 3, and 4 are sections taken approximately along the indicated lines 2 2, 3 3, and 4 4, respectively, of FIGURE 1,
FIGURE 5 is a View similar to FIGURE l but illustrating another embodiment of the invention and adjusted for another position of use,
FIGURE 6 is a side elevation of a sleeve that may be vused in place of the sleeve of the device shown in FIGURES l through 4, and,
FIGURE 7 is a section taken approximately along the indicated lines 7 7 of FIGURE 6.
In accordance with the invention, a tubular element 10 is threaded onto the muzzle of a shotgun barrel 11 and has a front sight 12. The element 10 has an intermediate, exteriorly threaded portion 13 of reduced diameter and a front portion provided with a plurality of circumferen t i ally spaced, longitudinally disposed, open-ended slots 14 defining a series of forwardly disposed, resilient choke lingers 15 of arcuate cross section with each linger shown as having a forwardly and inwardly tapering shoulder 16.
A sleeve 17 has the rear part of its bore threaded as at 18 to enable it to be attached to the threaded portion 13 of the element. The rear end of the sleeve bore is 3,161,979 Patented Dec. l22, 1964 counter-bored to .provide an annular skirt 19 overlying the element 10 adjacent the threaded portion 13. In the intermediate part of the bore, there is a forwardly and inwardly tapering or cone portion deiningfa shoulder 20.
It will be apparent that as the choke device is assembled by threading the sleeve 17 on the portion 13 of the element 10, the shoulders 16 and 20 engage until the ends of the fingers 15 are forced inwardly from their normal position to the desired extent. In theirnormal Iposition, the lingers 15 define a cylinder and when they are forced inwardly to the maximum extent,usually with their free ends in marginal contact, a full choke position is effected. Desired intermediate choke positions are provided such as so-called improved and modified positions. Additional positions are also provided, one between each successive two of the above referred to major positions. A ring 21 of resilient stock encircles the sleeve 17 and has one end 22 inturned to extend through a hole V23 to engage with the forward part of the element 10 to function as a click detent as it yieldably catches in the slots 14 as the sleeve 17 is turned. In practice, there are six slots 14 and six choke positions ranging from cylinder to full choke. These positions are marked on the sleeves (see FIGURES l and 5) and are readable with reference to the front sight 12.
The sleeve 17 has a plurality of apertures located both forwardly and rearwardly of the sleeve shoulder 20. These are shown as` consisting of a plurality of axially spaced series of transversely disposed slots 24, each series having three slots each, preferably, of alength greater than the width of a choke finger 15 and arranged so that each overlies two element slots 14 in any choke position and with corresponding slots of alternate series in alignment. One of the series of slots 24 rearwardly of the shoulder 20 is close thereto and is shown as extending therethrough in the cone rearwardly of its crest.
In the embodiment of the invention illustrated by FIG- URES 6 and 7, the element 10 is provided with a sleeve 17A which is identical to the sleeve 17 except that its shoulder 20A is at the forward end thereof. In the embodiment shown in FIGURE 5, the sleeve 17B has its slots 24B transversely disposed and arranged as a plurality of axially spaced series with the corresponding slots of each series being in alinement.
It is the rearward slots that are the most important feature of the invention. It will be noted that in any operative position of the choke device, even in the full choke position, the slots 14 are open. By providing slots rearwardly of the sleeve shoulders, gas is vented rearwardly of the ends of the lingers 15 which define the muzzle of the barrel. While the impingement of gas streams on the leading walls of the transverse sleeve slots is effective to reduce recoil, the venting of the choke area results in important improvement in shot patterns and shorter shot strings since it minimizes the effect of the choke on the gas streams passing therethrough.
1. In a shotgun choke device, a tubular element attachable at one end to the muzzle of a shotgun barrel and including at the other end a plurality of forwardly disposed, resilient choke lingers, said lingers being circumferentially spaced to provide intermediate slots, the outer surface of the free extremities of each finger including a forwardly and inwardly tapering end portion,
and a sleeve closely fitting over said lingers with its rear encl threaded on said element rearwardly of said fingers and including a forwardly and inwardly tapering, internal shoulder engageable with said linger end portions where- Y by, as said sleeve is threaded on said element, said fingers are forced inwardly and away from said sleeve to provide a choke effect and an annular space between the fingers and the sleeve, the width of said slots at the free extremities of the fingers decreasing as they are forced inwardly to increase the choke effect, said sleeve having a plurality of apertures in and rearwardly of said shoulder and overlying said element slots, the apertures in the shoulder becoming increasingly operative as Vents therefor as the choke effect increases.
2. The choke device of claim 1 in which the sleeve includes a forward portion the inside diameter of which is that of the forward extremity of the shoulder, the
forward sleeve portion also having a plurality of apertures.
References Cited in the file of this patent UNITED STATES PATENTS 1,892,522 White Dec. 27, 1932 2,656,637 Richards Oct. 27, 1953 2,662,326 Powell Dec. 15, 1953 2,663,961 White Dec. 29, 1953 2,759,286 Moore Aug. 21, 1956 2,977,702 Schacht Apr. 4, 1961 2,989,815 Hare .Tune 27, 1961