Cam mechanism for lens movement

A cam mechanism for a camera, comprising:

• a cam ring, a substantially helical cam groove formed in an inner surface of said cam ring, said helical cam groove having a first engaging surface;
• a lens frame housing a lens, said lens frame having a plurality of cam follower pins spaced circumferentially about said lens frame, each of said plurality of cam follower pins having a second engaging surface and extending substantially perpendicularly to an optical axis of said lens, said lens frame being movable along the optical axis by relative rotation of said lens ring and said lens frame about the optical axis;
• and
• a cross-section, along a plane containing the optical axis, of one of said first and second engaging surfaces being a curved surface and a cross-section, along a plane containing the optical axis, of a remaining one of said first and second engaging surfaces being a plurality of substantially straight surfaces.

A cam mechanism for moving a lens along a lens optical axis, said cam mechanism comprising:

• a cam ring having at least one cam groove formed in an inner surface of said cam ring;
• at least one cam follower pin extending substantially perpendicular to the lens optical axis and secured to a lens frame for moving said lens frame along the optical axis, a distal end of said at least one cam follower pin extending into and contactingly following said at least one cam groove, said at least one cam follower pin comprising a sole support of said lens frame;
• and
• contacting surfaces of said at least one cam groove and said at least one cam follower pin being shaped such that a contact area between said at least one cam groove and said at least one cam follower pin remains substantially constant within a predetermined range of angular positions of said at least one cam follower pin away from a position substantially perpendicular to the lens optical axis.

A cam mechanism for moving a lens along a lens optical axis, said cam mechanism comprising:

• a cam ring having at least one cam groove formed in an inner surface of said cam ring;
• at least one cam follower pin extending substantially perpendicular to the lens optical axis and secured to a lens frame for moving said lens frame along the optical axis, a distal end of said at least one cam follower pin extending into and contactingly following said at least one cam groove;
• and
• contacting surfaces of said at least one cam groove and said at least one cam follower pin being shaped such that contact between said at least one cam groove and said at least one cam follower pin remains substantially point contact within a predetermined range of angular positions of said at least one cam follower pin away from a position substantially perpendicular to the lens optical axis.