Importance

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Abstract

A telescopic sight is disclosed which may be used as a riflescope for viewing objects at different viewing distances. The telescopic sight is provided with a focus adjustment by longitudinal movement of the erector lens unit relative to an objective lens, an eyepiece lens and a reticle within the housing of such telescopic sight while maintaining a substantially constant magnification over the range of viewing distances. Such focus adjustment is accomplished in a simple manner with a rotatable knob coupled to the erector lens unit by a pin which is offset from the axis of rotation of such knob for orbital rotation, such axis of rotation extending laterally substantially perpendicular to the longitudinal movement of the erector lens unit. The focus adjustment pin is spring biased into engagement with a notch in a lens mounting tube containing the erector lens unit for longitudinal movement of the mounting tube in response to orbital rotation of the coupling pin by the focus adjustment knob. Rotation of the focus adjustment knob is limited by stops to less than 360.degree. and is preferably limited to a 180.degree. angle of adjustment. The objective lens and the eyepiece lens of the telescopic sight are fixed during focus adjustment of the erector lens unit, as is the reticle scale which is positioned between the eyepiece and the erector lens unit. As a result, telescopic sight is provided with substantially constant magnification throughout the range of focus adjustment so that the scope power changes less than 10.0% because the magnification of the erector lens unit changes less than 1.0% when focusing for objects at different viewing distances between infinity and 100 meters.

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First Claim