Patent ID: 6954587

Claim:
A zoom lens barrel comprising: a linear guide ring linearly movable along an optical axis without rotating; a moving frame which is supported by said linear guide ring to be linearly movable along said optical axis without rotating; a male helicoid formed on an outer peripheral surface of said moving frame; a rotatable ring which is coupled to said linear guide ring at a predetermined relative rotational position between said rotatable ring and said linear guide ring to be freely rotatable relative to said linear guide ring without moving along said optical axis relative to said linear guide ring; a female helicoid formed on an inner peripheral surface of said rotatable ring, said female helicoid being engaged with said male helicoid; a switching ring which is coupled to said rotatable ring at a predetermined relative rotational position between said switching ring and said rotatable ring to be freely movable along said optical axis relative to said rotatable ring and rotatable together with said rotatable ring, said switching ring being coupled to said moving frame to be freely rotatable relative to said moving frame without moving along said optical axis relative to said moving frame; a switching member which is supported by said linear guide ring to be freely movable in a circumferential direction of said linear guide ring within a predetermined range of movement without moving along said optical axis relative to said linear guide ring; and a switching-member moving groove which is formed on an inner peripheral surface of said switching ring to be engaged with a follower projection projecting from said switching member, wherein said switching-member moving groove includes a first inclined section, a switching section, a second inclined section and an assembling section, in that order from rear to front of said zoom lens barrel, wherein said first inclined section is shaped so that a lead angle thereof is the same as that of the threads of said female helicoid of said rotatable ring and so that a direction of inclination of said first inclined section is opposite to that of said threads of said female helicoid of said rotatable ring, wherein said follower projection is inserted in said switching-member moving groove via an open rear end of said first inclined section, wherein said switching section is shaped to extend parallel to said optical axis from a front end of said first inclined section, wherein said second inclined section is shaped to extend parallel to said first inclined section from a front end of said switching section, and wherein said assembling section extends rearwards from a front end of the second inclined section to be parallel to said optical axis.