Firearms – Implements – Sight devices
Reexamination Certificate
1998-10-21
2001-08-28
Jordan, Charles T. (Department: 3641)
Firearms
Implements
Sight devices
C042S119000
Reexamination Certificate
active
06279259
ABSTRACT:
TECHNICAL FIELD
The present invention relates to the field of telescopic rifle scopes and, in particular, to such rifle scopes with adjustment mechanisms having a resettable zero.
BACKGROUND OF THE INVENTION
It is necessary to adjust a rifle scope to a target at a specific distance because a bullet falls as it travels. Thus, a bullet will hit too low on a target when the target is farther away than the distance for which the scope is adjusted, unless the sight is adjusted to compensate for the fall. Most rifle scopes allow the shooter to compensate for the fall of the bullet by adjusting the scope so that the rifle is actually aimed higher when a more distant target is viewed in the cross hairs. The degree to which a rifle is aimed above the horizon is known as elevation, and adjusting the scope to raise the shooting angle is an elevation adjustment. A similar horizontal adjustment allows compensation for a sideways movement of a bullet caused by wind and is called a windage adjustment.
A shooter typically adjusts the elevation of the scope by turning a dial mounted on the scope body. The dial typically is marked with a scale around its diameter, and the body of the scope has an index mark marked on it. The shooter typically adjusts the scope so that a bullet will hit a target at a particular distance, e.g., 100 yards, when the target is in the cross hairs of the reticle. When the shooter wants to shoot at a target that is 200 yards away, he or she rotates the dial a predetermined angular distance so that the cross hairs will be accurately placed for a target at 200 yards. Many scopes use various types of click mechanisms to provide an audible or tactile indication for every increment of rotation. The shooter then does not need to take his or her eye from the target to adjust the elevation. Some scopes also provide a mechanism for adjusting the scale on the dial so that the shooter can align the zero mark of the scale with the index mark on the outer tube when the rifle is sighted in at a reference distance. The shooter can then easily return to the reference sighting or see how much he has adjusted the sight.
Rifle scopes are typically constructed of two tubes: an inner tube and an outer tube. The outer tube is fixed substantially parallel to the rifle barrel. The inner tube is typically fixed at one point to the inside of the outer tube by a ball-type joint, with the free end of the inner tube being movable in both the horizontal and vertical directions. A reticle or an erector lens assembly, or both, can be mounted at the movable end of the inner tube. The movable end can be adjusted up or down to adjust the elevation and horizontally to adjust for windage. Scope designs of this type are described in U.S. Pat. Nos. 3, 297, 389 and 4,408,842 of Gibson.
Many mechanisms have been used or proposed over the years to move the inner tube of rifle scopes to adjust the elevation and adjust for windage. Many such mechanisms use adjusting screws threaded into the outer tube that bear against the inner tube. As the shooter rotates the adjusting screw, it moves further inside the outer tube, pushing the inner tube. A spring located between the inner tube and the outer tube wall opposite the threaded adjusting screws biases the inner tube against the adjusting screws so that when the adjusting screws are rotated so as to move in an outward direction, the inner tube will follow the adjusting screw. The adjusting mechanism may be sealed to the outer tube to maintain within the interior of the outer tube a nitrogen gas charge necessary to prevent fogging and condensation on internal lens surfaces.
In these prior art designs, the rotating adjustment screws bear directly on the inner tube. Any out-of-roundness of the bearing end of the adjustment screw will cause changes to the sighting as the adjustment screw moves. As the windage and elevation adjustments change, the point of contact on the bearing end of the adjustment screw changes. Any deviation of the shape of the outer diameter of the inner tube from that of a perfect cylinder will cause deviations in the adjustment as the adjustment screws push against different points on the inner tube. Moreover, the contact of the adjustment screw end with the inner tube can cause wear on both parts. Wear can make the adjustment less even and can generate small particles that affect the optics and the adjustment mechanism.
SUMMARY OF THE INVENTION
An object of the invention is to provide a mechanism for adjusting a rifle scope for elevation and windage.
Another object of the invention is to provide such an adjustment mechanism with a smooth adjustment.
A further object of the invention is to provide such a mechanism having a resettable zero and a tactile adjustment indicator.
Yet another object of the invention is to provide such a mechanism having parts that can be replaced to change the characteristics of the adjustment without unsealing the outer tube.
These and other objects of the invention are accomplished by a rifle scope having an sighting adjustment mechanism, the adjustment mechanism itself, and methods of making and using the rifle scope and adjustment mechanism. The rifle scope includes an inner and an outer tube, the outer tube mounted on the rifle and the inner tube being sealed within the outer tube. The inner tube is fixed in a ball-type joint at one end, with the other end free. The adjustment mechanism adjusts the sight of the rifle scope by displacing the free end of the inner tube. The adjustment mechanism includes a threaded adjustment plunger that is rotationally fixed with respect to the body of the scope. The adjustment plunger threads onto a rotating member that is rotatably mounted to the body of the scope and includes a threaded portion. The rotating member is preferably an adjustment nut having a threaded internal bore. Alternatively, the rotating member includes male threads that mate with female threads on the adjustment plunger. As the rotating member rotates, the adjustment plunger, being prevented from rotating, moves in a direction perpendicular to the axis of rotation of the rotating member. As the threaded adjustment plunger moves inward or outward with respect to the outer tube, it adjusts the position of the inner tube.
The rotating member is rotated by a dial having an engaged position in which rotating the dial moves the adjustment plunger and a disengaged position in which rotating the dial does not move the adjustment plunger. The disengaged position is used to reset the zero on the dial after the rifle is sighted in at a particular distance.
Additional objects and advantages of this invention will be apparent from the following detailed description of preferred embodiments thereof which proceeds with reference to the accompanying drawings.
REFERENCES:
patent: 2165796 (1939-07-01), Humeston
patent: 2229637 (1941-01-01), Burton
patent: 2336107 (1943-12-01), Litschert
patent: 3058391 (1962-10-01), Leupold
patent: 3222987 (1965-12-01), Wrigglesworth
patent: 3280463 (1966-10-01), Stadler
patent: 3297389 (1967-01-01), Gibson
patent: 3826012 (1974-07-01), Pachmayr
patent: 3990155 (1976-11-01), Akin, Jr. et al.
patent: 4038757 (1977-08-01), Hicks et al.
patent: 4200355 (1980-04-01), Wiliams, Jr.
patent: 4247161 (1981-01-01), Unertl, Jr.
patent: 5363559 (1994-11-01), McCarty
patent: 5513440 (1996-05-01), Murg
patent: 598306 (1948-02-01), None
patent: 2213959 (1989-01-01), None
Buckley Denise J
Jordan Charles T.
Leupold & Stevens, Inc.
Stoel Rives LLP
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