JPH04251231A - Opening and closing mechanism for lens cover - Google Patents

Abstract

PURPOSE:To open and close a sliding type lens cover driven by motor by a compact drive mechanism. CONSTITUTION:When a sliding member 30 is moved by a rack 40 moved by a motor, a planet gear 34 provided on the sliding member 30 is rotated by a gear 24 provided on a frame 20 associated with the moving of the sliding member 30. Therefore, a gear 12 meshing with this planet gear 34, that is, the lens cover 10 is relatively moved by the rotating amount of the planet gear 34 with respect to the planet gear 34. As a result, the lens cover 10 is moved twice as much as the moving amount of the sliding member 30 by the moving of the sliding member 30 and the rotation of the planet gear 34.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens cover opening/closing mechanism, and more particularly to a lens cover opening/closing mechanism for electrically opening/closing a sliding lens cover disposed in front of a photographing lens of a video camera or the like.

0002

2. Description of the Related Art In general, most lens covers for video cameras are detachable from the photographic lens. This is because the aperture of the shooting lens of a video camera is large, and the shooting lens protrudes from the camera body.
This is due to reasons such as there being no space for a built-in camera lens cover.

On the other hand, in recent years, a video camera has been proposed that is provided with a sliding lens cover that can be opened and closed manually (Japanese Patent Application No. 142767/1999). It is also conceivable to electrically open and close the sliding lens cover.

0004

By the way, as an example of driving a sliding lens cover electrically, a rack is provided on the lens cover side, a pinion is engaged with the rack, and the pinion is rotated to drive the lens cover. It is possible to move the However, in this case, the lens cover must be provided with a rack that is longer than the lens cover, which increases the storage space when the lens cover is opened.

[0005]Also, it is possible to open and close the lens cover by rotating a lever, but in this case, the length of the lever required to open and close the lens cover becomes long, and the space required for rotating this lever is also large. Become. The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a lens cover opening/closing mechanism that can electrically open/close a sliding lens cover using a more compact drive mechanism.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention is arranged to be movable between a front position of a photographic lens and a retracted position where it is retracted from the photographic lens, and the photographic lens is opened and closed. a first gear fixed to the lens cover, the first gear having teeth formed along the moving direction of the lens cover, and a first gear fixed to the photographing lens side; A second gear is provided facing the first gear, and a second gear is provided to be movable in the same direction as the lens cover, and is connected to the first gear and the second gear, respectively. a sliding member having planetary gears that mesh with each other; and moving the sliding member electrically;
The present invention is characterized by comprising a drive means for moving the lens cover between a position in front of the photographic lens and a retracted position where it is retracted from the photographic lens via the planetary gear and the first gear.

[0007]

According to the present invention, when the slide member is moved by the drive means, the planetary gear provided on the slide member is rotated by the second gear as the slide member moves. Therefore, the first gear (lens cover) that meshes with the planetary gear moves relative to the planetary gear by the amount of rotation of the planetary gear. That is, the lens cover moves approximately twice the amount of movement of the slide member due to the movement of the slide member and the rotation of the planetary gear.

Therefore, even if the length of the first gear provided on the lens cover is shorter than the lens cover, the amount of movement required to open and close the lens cover can be obtained, and the mechanism can be built into the movement silhouette of the lens cover. , resulting in a more compact mechanism.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the lens cover opening/closing mechanism according to the present invention will be described in detail below with reference to the accompanying drawings. 1 and 2 are views showing an embodiment of the lens cover opening/closing mechanism according to the present invention, respectively. FIG. 1 shows the lens cover in the open state, and FIG. 2 shows the lens cover in the closed state. .

The lens cover 10 is moved between a retracted position (lens cover open state) where it is retracted from a photographic lens (not shown) and a front position of the photographic lens (lens cover closed state) by a guide rail 22 etc. formed on the frame 20. It is arranged so that it can be moved freely. Further, the lens cover 10 is provided with a gear 12 whose teeth are along the moving direction of the lens cover 10.

On the other hand, the lens cover 1 is attached to the frame 20.
A gear 24 facing the zero gear 12 is provided. Further, a guide groove 26 is formed in the frame 20, and the slide member 30 is movably guided by the guide groove 26. A pin 32 to which a driving force is applied from a rack 40 is implanted in the slide member 30, and a planetary gear 3 meshes with the gear 12 and the gear 24, respectively.
4 are arranged.

The rack 40 has a connecting member 42 for transmitting driving force to the pin 32, and as described later, the rack 40 has a connecting member 42 for transmitting driving force to the pin 32.
0 moves in the left-right direction, the connecting member 42 and the pin 32
The driving force is transmitted to the slide member 30 via. Thereby, the slide member 30 is guided by the guide groove 26 and moves. Although the slide member 30 is guided to move in an arc, the connecting member 42 is formed with a long hole 42A, so the pin 32 is inserted through the long hole 42A.
The driving force can be transmitted to.

When the slide member 30 is moved as described above, the planetary gear 34 provided on the slide member 30 is rotated by the gear 24 provided on the frame 20. The rotation of this planetary gear 34 is caused by the rotation of the gear 12,
That is, the signal is transmitted to the lens cover 10 and moves the lens cover 10 relative to the planetary gear 34. That is, when the slide member 30 is moved by the rack 40, the lens cover 10 is moved by the movement of the slide member 30 and the planetary gear 34.
The rotation of the slide member 30 allows the slide member 30 to move approximately twice as much as the amount of movement. As a result, even if the length of the gear 12 provided on the lens cover 10 is short, the lens cover 1
0 can be moved by the amount of movement required to open and close the lens cover 10, and a drive mechanism can be built into the moving silhouette of the lens cover 10.

FIG. 3 is a plan view of the lens cover opening/closing mechanism shown in FIG. 2, showing the drive system for moving the rack 40 in detail. As shown in the figure, the motor 50
to the rack 40 via the worm 51 and gears 51 to 57.
The driving force is transmitted to. As a result, the rack 40 is moved in the left-right direction in FIG. 3, and the lens cover 10 is opened and closed as described above.

FIG. 4 is a diagram in which the gear train from the motor 50 to the rack 40 in FIG. 3 is arranged in a straight line. As shown in the figure, the rotation of the motor 50 is caused by a worm 51, gears 51 to 55,
5, and is transmitted to gear 56A. gear 5
The rotation of 6A is transmitted via shaft 56B to gear 56C, which is attached to shaft 56B with a predetermined frictional force. The rotation of the gear 56C is transmitted to the gear 57A, then transmitted to the coaxially provided gear 57C via the coil spring 57B, and further transmitted to the rack 40 via the gear 57C.

According to the gear train having the above configuration, when the lens cover 10 is closed and an attempt is made to open the lens cover 10 by an external force, the gear 57 is opened via the rack 40.
C is rotated, but since the gear 57A is prevented from rotating by the gear 56C, the amount of rotation of the gear 57C is absorbed by the coil spring 57B. Therefore, lens cover 1
When the external force is removed from 0, the lens cover 10 is closed by the rotational force stored in the coil spring 57B.

On the other hand, a coil spring 57 is attached to the lens cover 10.
More than the amount of rotation that can be absorbed by B (gear 56 relative to shaft 56B)
When an external force (more than a predetermined frictional force of C) is applied, gear 5
6C rotates to prevent excessive external force from being applied to the gear train. In this embodiment, the lens cover is moved in an arc shape, but the lens cover is not limited to this, and may be moved in a straight line.

[0018]

As explained above, according to the lens cover opening/closing mechanism according to the present invention, the lens cover can be moved approximately twice as much as the amount of movement of the slide member by the movement of the slide member and the rotation of the planetary gear. be able to. As a result, the sliding lens cover can be electrically opened and closed using a more compact drive mechanism, and the mechanism can be built into the moving silhouette of the lens cover.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the lens cover opening/closing mechanism according to the present invention, and is a diagram showing the lens cover in an open state.

FIG. 2 is a diagram showing a state in which the lens cover in FIG. 1 is closed.

FIG. 3 is a plan view of the lens cover opening/closing mechanism shown in FIG. 2;

4 is a side view of the gear train from the motor to the rack shown in FIG. 3 arranged in a straight line; FIG.

[Explanation of symbols]

10...Lens cover 12, 24...gear 20...Frame 30...Slide member 32...pin 34... Planetary gear 40...Rack 42...Connecting member 50...Motor

Claims (1)

[Claims] 1. A slide-type lens cover that is movably arranged between a front position of the photographic lens and a retracted position for retracting from the photographic lens and for opening and closing the photographic lens, and a sliding lens cover that is fixed to the lens cover. a first gear having teeth formed along the moving direction of the lens cover, and a second gear fixed to the photographing lens side, facing the first gear. a second gear provided therein; a slide member having a planetary gear that is movably disposed in the same direction as the lens cover and meshes with the first gear and the second gear; and the slide member is electrically operated. and a driving means for moving the lens cover between a front position of the photographing lens and a retracted position where it is retracted from the photographic lens via the planetary gear and the first gear. Lens cover opening/closing mechanism.