Patent ID: 7612958

Claim:
A telescopic sight including a zoom mechanism comprising: a lens barrel of the telescopic sight said lens barrel having an optical axis, said lens barrel including a zoom ring which is rotatably mounted at an outer periphery of said lens barrel; an annular gear which is mounted at an inner periphery face of the zoom ring for rotation with said ring, said annular gear having teeth projecting inwardly in a direction toward the optical axis of said lens barrel; a circumferential gear which is rotatably mounted at an inner periphery of the lens barrel said circumferential gear mounted concentrically with and axially aligned with the annular gear, said circumferential gear including teeth extending outwardly away from the axis of said lens barrel; an intermediate gear rotatably mounted to said zoom ring and interposed between said annular gear and said circumferential gear to transmit rotation of said zoom ring and annular gear to the circumferential gear; a cam tube which is rotatably mounted in the lens barrel for moveably supporting telescoping lenses; and a transmission mechanism extending between said cam tube and said circumferential gear which transmits rotation of the circumferential gear to said cam tube, wherein said transmission mechanism comprises a groove in one of said cam tube and circumferential gear and a protrusion on the other one of said cam tube and circumferential gear for engaging said circumferential gear with said cam tube.