Retracting mechanism of a zoom lens barrel

A retracting mechanism of a zoom lens barrel including a first lens group, a second lens group and a third lens group, in that order from an object side, wherein said first lens group and said third lens group are integrally moved along an optical axis during a variation of a focal length, and wherein at least one of said first lens group and said third lens group is moved relative to the other to reduce a distance therebetween when said zoom lens barrel is fully retracted, said retracting mechanism comprising:

• a first lens group moving ring, for supporting said first lens group, which is linearly guided along said optical axis;
• a second lens group moving ring, for supporting said second lens group, which is linearly guided along said optical axis;
• a third lens group moving ring, for supporting said third lens group, which is linearly guided along said optical axis, said third lens group moving ring being allowed to approach said first lens group moving ring and being prevented from moving away from said first lens group moving ring beyond a moving limit relative to said first lens group moving ring;
• a cam mechanism for moving said first lens group moving ring and said second lens group moving ring in respective moving manners independent of each other along said optical axis;
• a second lens group support frame which supports said second lens group;
• an intermediate member which is supported by said second lens group moving ring to be movable along said optical axis while being prevented from moving forward beyond a forward moving limit of said second lens group support frame relative to said second lens group moving ring, said second lens group support frame being screw-engaged into said intermediate member;
• and
• a biasing device for biasing said third lens group moving ring in a direction away from said first lens group moving ring,
• wherein said biasing device functions between said intermediate member and said third lens group moving ring.