Control mechanism for varifocal objective

Claim 2

A varifocal objective comprising: a front lens group centered on an axis including a first pair of shiftable components each movable along said axis at a rate different from that of the other component; a rear lens group coaxial with said front lens group including a second pair of shiftable components each movable along said axis at a rate different from that of the other component; a first rotable element; first cam means operatively connecting said first rotatable element with said first pair of components; a second rotatable element; second cam means operatively connecting said second rotatable element with said second pair of components; and a common control mechanism for all said components including a rotatable drive member mechanically coupled with both said elements for rotating same.

Claim 3

A varifocal objective as defined in claim 1, further comprising a diaphragm of variable aperture provided with adjusting means and coaxially interposed between said front and rear lens groups, said control mechanism being operatively coupled with said adjusting means for changing said aperture upon rotation of said second element.

Claim 4

A varifocal objective as defined in claim 2 wherein said control mechanism includes a shaft extending parallel to the axis of said components, said diaphragm being mechanically coupled with said shaft.

Claim 5

A varifocal objective as defined in claim 3 wherein said shaft is provided with first gear means engaging said first element, second gear means engaging said second element and third gear means engaging said diaphragm.

Claim 6

A varifocal objective as defined in claim 4 wherein said adjusting means includes a mounting ring coupled with said third gear means and a setting ring coaxially spaced from said mounting ring, said diaphragm having a set of iris leaves pivoted to both said rings, said setting ring being rotatable independently of said mounting ring.

Claim 7

A varifocal objective as defined in claim 4 wherein said first cam means comprises formations on said first element effective to shift said first pair of components only during a first phase of angular displacement of said shaft, said second cam means comprising formations on said second element effective to shift said second pair of components only during a second phase of angular displacement of said shaft.

Claim 8

A varifocal objective as defined in claim 6 wherein said adjusting means is ineffectual to change said aperture in said first phase of angular displacement.

Claim 9

A varifocal objective as defined in claim 3 wherein said control mechanism includes differential gearing having an input coupled with said drive member, a first output coupled with said first element and a second output coupled with said shaft, the shaft being in positive engagement with said diaphragm and with said second element.

Claim 10

A varifocal objective as defined in claim 8 wherein said elements are provided with detents for releasably arresting said first element in a second phase and said second element in a first phase of angular displacement of said shaft.

Claim 11

A varifocal objective comprising: a front lens group centered on an axis including a first pair of shiftable components each movable along said axis at a rate different frOm that of the other component; a rear lens group coaxial with said front lens group including a second pair of shiftable components each movable along said axis at a rate different from that of the other component; and drive means rotatable about said axis within a range of angular positions divided into a first and a second subrange, said drive means being provided with a first pair of generally helicoidal camming formations respectively engaging said first pair of components and with a second pair of generally helicoidal camming formations respectively engaging said second pair of components, said first pair of camming formations having portions of zero pitch engaging said first pair of components in said first subrange, said second pair of camming formations having portions of zero pitch engaging said second pair of components in said second subrange.

Claim 12

A varifocal objective comprising: a front lens group centered on an axis including a first pair of shiftable components each movable along said axis at a rate different frOm that of the other component; a rear lens group coaxial with said front lens group including a second pair of shiftable components each movable along said axis at a rate different from that of the other component; and drive means rotatable about said axis within a range of angular positions divided into a first and a second subrange, said drive means being provided with a first pair of generally helicoidal camming formations respectively engaging said first pair of components and with a second pair of generally helicoidal camming formations respectively engaging said second pair of components, said first pair of camming formations having portions of zero pitch engaging said first pair of components in said first subrange, said second pair of camming formations having portions of zero pitch engaging said second pair of components in said second subrange.

Claim 13

A varifocal objective as defined in claim 10 wherein said drive means comprises a first sleeve centered on said axis and provided with said first pair of camming formations, a second sleeve centered on said axis and provided with said second pair of camming formations, and transmission means for jointly rotating said sleeves at different rates.