Power transmission and camera

Abstract

A power transmission capable of regulating the disengagement of a nut part from a screw part, and the like are provided. The power transmission is constructed of a rotation shaft having a thread formed on a periphery thereof; a nut member capable of being opened and closed, the nut member having a thread engaged with the thread of the rotation shaft, and pinching the rotation shaft and moving as the rotation shaft is rotated; a regulating part enabling movement of the nut member by regulating opening of the nut member; and a regulation releasing part capable of releasing engagement between the nut member and the rotation shaft by opening the nut member.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the construction of a camera to which the present invention is applied;

FIG. 2 is a sectional view of a lens barrel in a preferred embodiment of a camera to which the present invention is applied;

FIG. 3 is a sectional view taken along the line indicated with arrows III-III in FIG. 2;

FIG. 4 is an enlarged view of the site IV in FIG. 2;

FIG. 5 is a sectional view taken along the line indicated with arrows V-V in FIG. 4;

FIG. 6 is an enlarged view of a key part showing a state where the nut is in a release regulating region in the camera of FIG. 2;

FIG. 7 is a sectional view taken along the line indicated with arrows VII-VII in FIG. 6;

FIG. 8 is an enlarged view of a key part showing a state where the nut is in a lower releasable region in the camera of FIG. 2;

FIG. 9 is a sectional view taken along the line indicated with arrows IX-IX in FIG. 8; and

FIG. 10 is a sectional view taken along the line indicated with arrows X-X in FIG. 8.

Claims

1. A power transmission comprising: a rotation shaft having a thread formed on a periphery thereof;a nut member capable of being opened and closed, the nut member having a thread engaged with the thread of the rotation shaft, and pinching the rotation shaft and moving as the rotation shaft is rotated;a regulating part enabling movement of the nut member by regulating opening of the nut member; anda regulation releasing part capable of releasing engagement between the nut member and the rotation shaft by opening the nut member.

2. The power transmission according to claim 1, wherein the regulation releasing part releases the engagement between the nut member and the rotation shaft by opening the nut member when a force of at least a predetermined value is applied between the thread of the nut member and the thread of the rotation shaft.

3. The power transmission according to claim 1, further comprising: a guide member provided with the regulating part and the regulation releasing part.

4. The power transmission according to claim 3, wherein the guide member is arranged substantially parallel to the rotation shaft.

5. The power transmission according to claim 4, wherein the regulation releasing part releases the engagement between the nut member and the rotation shaft by opening the nut member when a force of at least a predetermined value is applied between the thread of the nut member and the thread of the rotation shaft.

6. The power transmission according to claim 4, wherein, the regulating part is formed in a range of the guide member corresponding to a moving range of the nut member; and the regulation releasing part is formed in a range of the guide member corresponding to outside of the moving range of the nut member.

7. The power transmission according to claim 4, wherein, the regulating part is a surface opposed to the nut member and regulating the opening of the nut member so as not to release the engagement between the thread of the rotation shaft and the thread of the nut member; and the regulation releasing part is a recess or an opening opposed to the nut member and opening the nut member so as to release the engagement between the thread of the rotation shaft and the thread of the nut member.

8. The power transmission according to claim 7, wherein the nut member has a projection smaller than the recess or the opening at a position opposed to the guide member.

9. The power transmission according to claim 8, wherein, the regulating part is formed in a range of the guide member corresponding to a moving range of the nut member; and the regulation releasing part is formed in a range of the guide member corresponding to outside of the moving range of the nut member.

10. A camera comprising: a power transmission having a rotation shaft having a thread on a periphery thereof; a nut member capable of being opened and closed, the nut member having a thread engaged with the thread of the rotation shaft, and pinching the rotation shaft and moving as the rotation shaft is rotated; a regulating part enabling movement of the nut member by regulating opening of the nut member; and a regulation releasing part capable of releasing engagement between the nut member and the rotation shaft by opening the nut member;an actuator to rotate the rotation shaft of the power transmission; anda movable lens connected to the nut member of the power transmission.

11. The camera according to claim 10, wherein the regulation releasing part releases the engagement between the nut member and the rotation shaft by opening the nut member when a force of at least a predetermined value is applied between the thread of the nut member and the thread of the rotation shaft.

12. The camera according to claim 10, wherein, the power transmission has a guide member provided with the regulating part and the regulation releasing part each being disposed parallel to the rotation shaft;the regulating part is formed in a range of the guide member corresponding to a moving range of the nut member; andthe regulation releasing part is formed in a range of the guide member corresponding to outside of the moving range of the nut member.

13. The camera according to claim 12, wherein, the regulating part is a surface opposed to the nut member and regulating the opening of the nut member so as not to release the engagement between the thread of the rotation shaft and the thread of the nut member;the regulation releasing part is a recess or an opening opposed to the nut member and opening the nut member so as to release the engagement between the thread of the rotation shaft and the thread of the nut member; andthe regulation releasing part releases the engagement between the nut member and the rotation shaft by opening the nut member when a force of at least a predetermined value is applied between the thread of the nut member and the thread of the rotation shaft.