Extendable pivot shaft mechanism, and an extendable pivot shaft mechanism of a camera for pivoting a rotatable grip on a camera body

An extendable pivot shaft mechanism of a camera for pivoting a rotatable grip on a camera body to allow said rotatable grip both to rotate about a rotational axis and to move along said rotational axis relative to said camera body,

• wherein said extendable pivot shaft mechanism comprises an inner shaft, a middle cylinder and an outer cylinder which are concentrically arranged about said rotational axis,
• wherein said inner shaft and said outer cylinder are fixed to one and the other of said grip and said camera body, respectively,
• wherein one of said inner shaft and said outer cylinder serves as a rotatable shaft element which is rotatable about said rotational axis relative to said middle cylinder,
• wherein the other of said inner shaft and said outer cylinder serves as a linearly movable shaft element which is linearly movable along said rotational axis relative to said middle cylinder;
• and
• a click-stop mechanism, provided between said middle cylinder and said linearly movable shaft element, for stopping said linearly movable shaft element moving along said rotational axis relative to said middle cylinder with a click action when said middle cylinder and said linearly movable shaft element relatively move along said rotational axis;
• wherein said click-stop mechanism comprises:
• at least one click recess formed on one of an outer peripheral surface of said middle cylinder and an inner peripheral surface of said outer cylinder;
• at least one ball accommodation hole formed on the other of an outer peripheral surface of said middle cylinder and in inner peripheral surface of said outer cylinder extending in a radial direction, said ball accommodation hole facing said click recess when the axial positions of said ball accommodation hole and said click recess are aligned;
• at least one click ball accommodated in said ball accommodation hole to be movable therein in said radial direction;
• and
• at least one spring accommodated in said ball accommodation hole for biasing said click ball toward a direction to engage said click recess.