Rifle scope having compensation for elevation and drift

• US 4,255,013 A
• Filed: 05/17/1979
• Issued: 03/10/1981
• Est. Priority Date: 05/17/1979
• Status: Expired due to Term

• Current Assignee: Ralph G. Allen
• Original Assignee: John E. Mcnair
• Inventors: Allen, Ralph G.
• Primary Examiner(s): Henry, Jon W.
• Application Number:
  US06/040,071
• Time in Patent Office: 663 Days
• Field of Search: 350/10, 350/42, 350/43, 350/44, 356/247
• US Class Current: 359/422
• CPC Class Codes: F41G 1/38 Telescopic sights specially adapted for smallarms or ordnance telescopic sights in general G02B; Supports or mountings therefor
• CPC Class Codes: G02B 23/06 having a focussing action, e.g. parabolic mirror
• CPC Class Codes: G02B 23/145 Zoom viewfinders
• CPC Class Codes: G02B 27/32 Fiducial marks and measuring scales within the optical system

Abstract

A variable power telescopic gunsight is shown with an automatic correction factor for elevation and/or drift. As the magnification is adjusted by a rotatable means on the gunsight which typically moves a pair of lens in response to camming action, a third longitudinal movement is provided in the gunsight in response to the rotation with appropriate camming surfaces to compensate for normal drop of the bullet by providing elevation of line of sight of the scope up or down. The same rotation action used to change the magnification can provide another longitudinal movement of another camming surface to compensate for drift by changing the line of sight of the scope to the right or left.

Claims

1. A variable magnification power rifle scope constructed along an axis comprising:

a housing adapted to be attached to a gun;

a lens tube movably mounted in said housing and having rotatable means to longitudinally position lens means in said tube for varying magnification;

cam means operable by said rotatable means;

said cam means providing non-linear longitudinal movement of a contact point against a cam surface for tilting line of sight in response to said rotatable means; and

adjustable means for changing said tilt of said line of sight by adjusting said cam surface to adapt said scope to different rifle/cartridge combinations and to facilitate sighting in of said scope.

2. The invention of claim 1 wherein said cam surface comprises a rigid straight cam operable with said contact point.

3. The invention of claim 1 wherein said cam surface comprises a curved rigid cam operable with said contact point.

4. The invention of claim 1 wherein said cam surface comprises a flexible adjustable cam operable with said contact point, curve of said flexible adjustable cam being set by adjusting means.

5. The invention of claim 1 includes a shear plate or prism operable by said contact point to deflect said line of sight.

6. The invention of claim 1 wherein said cam means includes cam followers in slots of said lens tube and said rotatable means.

8. The invention of claim 1, 2, 3, 4, 5, 6 or 7 further comprising a drift compensating means with a second contact point of second cam means responsive to said rotation for adjusting said line of sight an angular amount sufficient to compensate for drift.

9. The invention of claim 1, 2, 3, 4, 5, 6 or 7 further comprising a drift compensating means normal to said elevating means, said drift compensating means angularly displacing said line of sight an angular amount sufficient to compensate for drift of a projectile proportional to range.

10. The invention of claim 1 wherein said rotatable means is a magnification control ring with visual indications thereon to give range upon adjusting magnification to bracket an image of a target of known dimensions between reticle stadia marks.

7. A variable magnification power rifle scope constructed along an axis comprising:

a housing adapted to be attached to a gun;

a lens tube movably mounted in said housing and having rotatable means to longitudinally position lens means in said tube for varying magnification;

a raised spiral cam on said rotatable means and operable by said rotatable means;

said raised spiral cam providing non-linear longitudinal movement of a contact point against the cam surface for tilting line of sight in response to said rotatable means; and

adjustable means for changing said tilt of said line of sight by adjusting said cam surface to adapt said scope to different rifle/cartridge combinations and to facilitate sighting in of said scope.

11. A telescopic gun sight having optical means for establishing a line of fire and for magnifying a shooter'"'"'s view of a target and moveable adjusting means for changing degree of magnification, reticle means in said line of sight for indicating the degree of magnification of said target, said target having a known dimensions whereby movement of said moveable adjusting means to establish a predetermined relation between said shooter'"'"'s view of said target and said reticle means is indicative of range to said target, said telescopic gun sight comprising:

a housing adapted to be attached to a gun;

a lens tube mounted in said housing;

said optical means including at least one optical element within and moveable along said lens tube;

said moveable adjusting means comprising a sleeve rotatable with inset housing and first means responsive to said rotation of said sleeve for positioning said optical means along said lens tube, second means responsive to said rotation to non-linearly longitudinally position a contact point on a bearing surface adjustable fixed within said scope housing;

elevating means tilting said line of sight in response to said non-linear longitudinal variation of said contact point to require a proper position of said gun with correct sight elevation upon aiming at said target for shooting;

said elevating means comprising cam means for converting said non-linear longitudinal variation of said contact point to angular motion of elevation proportional to range and second optical means for deflecting said line of sight through said lens system, said deflecting means being responsive to said non-linear longitudinal positioning of said contact point to deflect the line of sight proportional to magnification thereby providing angular elevation required for range to target;

drift compensating means with a second contact point of second cam means responsive to said rotation for adjusting said line of sight at angular amounts sufficient to compensate for drift.