JP2000231140A - Barrier opening/closing mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To open/close a lens barrier by driving to rotate a drive ring for the lens barrier arranged at the leading end of a lens barrel by the rotation of the rotary barrel. SOLUTION: A cam groove 65 is formed in the rotary barrel 6, and an actuating lever 12 with a cam pin 12a engaged with the cam groove 65 is moved in an optical axis direction in accordance with the rotation of the rotary barrel 6 near the collapsed position of the lens barrel 1, then, the barrier driving ring 24 is rotated so as to open/close the lens barrier 22.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a barrier opening / closing mechanism for a camera that opens and closes a lens barrier in conjunction with extension and retraction of a lens barrel.

[0002]

2. Description of the Related Art In general, in a camera in which a lens barrel is extended from a camera body to take a picture, a lens barrel is retracted from a retracted position (a position in which the lens barrel is housed in the camera body). A barrier opening / closing mechanism is provided that opens the lens barrier (lens cover) at the tip of the lens barrel when the lens barrel is extended to a possible position, and retracts the lens barrier from the wide end of the lens barrel to the collapsed position.

For example, in a barrier opening / closing mechanism disclosed in Japanese Utility Model Publication No. 7-55546, a lens barrel that can be extended and retracted with respect to a camera body moves forward and backward along the optical axis together with extension and retraction of the lens barrel. A cam member having an inclined surface is provided on the key member provided in the lens barrel, and the tip of a drive arm extending in the optical axis direction from a barrier drive ring that opens and closes the lens barrier by rotation contacts the inclined surface. In contact therewith, the barrier driving ring rotates by opening and closing the key member to open and close the lens barrier.

[0004]

However, in the above-described prior art, a cam member having an inclined surface must be provided on a key member which advances and retreats along the optical axis when the lens barrel is extended and retracted. There was a problem that it was difficult to make.

In view of the above circumstances, it is an object of the present invention to provide a barrier opening / closing mechanism that is easy to make and that reliably opens and closes a lens barrier.

[0006]

A barrier opening / closing mechanism according to the present invention includes a rotating cylinder rotatable about an optical axis, and the rotation of the rotating cylinder allows the lens barrel to be extended and retracted with respect to the camera body. A lens barrel disposed at the tip of the lens barrel for opening and closing a lens opening; and a lens barrier disposed rotatably about the optical axis in the lens barrel, the lens barrier being rotated by the rotation. A cam groove provided in the rotary barrel, and a cam follower engaged with the cam groove, wherein the rotary barrel near the retracted position of the lens barrel is provided. An operating lever that moves in the optical axis direction along with the rotation to rotate the barrier drive ring.

[0007]

According to the present invention, since the operating lever for rotating the barrier drive ring is configured to be driven by the cam groove provided in the rotary cylinder, it is easy to form the cam groove. In addition, since the rotation of the rotary cylinder is transmitted to the barrier drive ring via the operating lever, there is an advantage that the opening and closing operation of the lens barrier is smooth and reliable.

[0008]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an exploded perspective view of a zoom lens barrel provided with an embodiment of a barrier opening / closing mechanism according to the present invention. FIGS. 2 to 4 show the lens barrel shown in FIG. FIG. 2 shows a retracted (bottom) state, FIG. 3 shows a wide-angle photographing (wide) state, and FIG. 4 shows a telephoto photographing (telephoto) state.

In the figure, a lens barrel 1 is extended and retractable with respect to a camera body 11, and enables telephoto and wide-angle photography by its extending and retracting operation. From the front, the lens barrier 2
A moving barrel 5 incorporating a front lens group 3 held by a lens holder 31 and a shutter block 4 having a shutter 4a; a rotating barrel (intermediate barrel) 6;
The rear lens group 7, the straight-moving key barrel 8, the fixed barrel 9, and the key plate 10 held at 1 are arranged concentrically. The lens barrel 1 has a structure in which a rotating barrel 6 and a moving barrel 5 are telescopically extended and retracted with respect to a fixed cylinder 9 fixed to a camera body 11.

In the lens barrel 1, a helicoid mechanism is used for extending and retracting the rotary cylinder 6 and the movable cylinder 5. That is, the rotating cylinder 6 is arranged inside the fixed cylinder 9, the moving cylinder 5 is arranged inside the rotating cylinder 6, and the helicoid 91 formed on the inner peripheral surface of the fixed cylinder 9.
A helicoid 61 formed on the outer peripheral surface of the rear part of the rotary cylinder 6.
Are screwed into each other to form a helicoid 6 formed on the inner peripheral surface of the rotary cylinder 6.
2, a helicoid 5 formed on the outer peripheral surface of the rear part of the moving cylinder 5.
1 is screwed.

A straight key barrel 8 is inserted inside the movable barrel 5, and a key plate 10 fixed to the rear end of the straight key barrel 8 with screws is moved only in the optical axis direction with respect to the fixed barrel 9. The rotation cylinder 6 is engaged with the rotation cylinder 6 and is locked to the rear end of the rotation cylinder 6 so as to allow the rotation of the rotation cylinder 6. A guide groove 81 extending in the optical axis direction for moving the movable cylinder 5 straight and a guide groove 82 extending in the optical axis direction for moving the rear group lens 7 straight are formed on the peripheral surface of the straight key barrel 8. I have. A ridge 53 formed on the inner peripheral surface of the movable cylinder 5 and extending in the optical axis direction is engaged with the guide groove 81.

On the inner peripheral surface of the rotary cylinder 6, the helicoid 6
2 and a cam groove 63 for driving the rear group lens 4
Are formed on the outer peripheral surface of the rear lens group holder 71.
Three cam pins (cam followers) 72 projecting radially at equal angular intervals of 0 ° pass through the guide grooves 82 and engage with the cam grooves 63 of the rotary cylinder 6. Further, a drive gear (not shown) which is provided with a long tooth surface extending in the optical axis direction and is rotated by a motor is attached to the outside of the fixed cylinder 9. When the drive gear rotates due to meshing with the gear teeth 64 formed on the helicoid 61, the rotating barrel 6 advances and retreats in the optical axis direction while rotating with respect to the fixed barrel 9, and the straight-moving key barrel 8. Moves back and forth in the optical axis direction together with the rotary cylinder 6 without rotating with respect to the fixed cylinder 9. Therefore, the front group lens 3 and the rear group lens 4 are configured to move straight in the optical axis direction.

A lens barrier 2 for opening and closing the lens opening 52 is attached to the tip of the movable cylinder 5. The lens barrier section 2 includes a front cover 21, a pair of barrier pieces 22, 22, a barrier substrate 23, and a barrier drive ring 24.

FIGS. 5 and 6 are schematic front views showing opening and closing operations of the barrier pieces 22 and 22 of the lens barrier section 2, and FIGS.
And FIG. 8 is a schematic rear view showing a driving mechanism of the barrier pieces 22 and 22. 5 and 7 show the barrier piece 2
6 and 8 show the open state of the barrier pieces 22 and 22.
22 shows the closed state.

The lens barrier section 2 is formed on a barrier substrate 23 having a photographing opening 23a by a pair of plate-like members whose roots are pivotally supported by shafts 23b, 23b extending in the optical axis direction (perpendicular to the plane of the paper). Each of the barrier pieces 22 has a linear edge 22a that abuts or slightly overlaps with each other in the closed state shown in FIG.
It has.

At the base of each barrier piece 22, a pin 22b extending in the optical axis direction at a position separated from the pivot point by the shaft 23b by a predetermined distance is fixedly provided through the barrier substrate 23. Then, the barrier piece 2 is attached to the pin 22b.
One end of a spring 26 that urges the barrier drive ring 24 in the closing direction is locked, and as will be described later, when the lens barrier is opened, the projection 24a of the barrier drive ring 24 abuts and the barrier piece 2a contacts.
2 is configured to pivot in the opening direction.

As shown in FIGS. 7 and 8, a barrier drive ring 24 is provided on the barrier substrate 23 so as to be rotatable around the optical axis over a predetermined angle range. The barrier drive ring 24 includes a pair of projections 24a, 24a for pivoting the respective barrier pieces 22 to the open position, and a spring for urging the barrier drive ring 24 clockwise in FIGS. Locking piece 24b for locking one end of 25
And a locking piece 24 for locking one end of a spring 26 for urging the barrier pieces 22 in the closing direction.
c and 24c and a connecting lever 24d for rotating the barrier drive ring 24 counterclockwise in FIGS. 7 and 8 are integrally provided on the outer periphery thereof. The connecting lever 24 d extends rearward in the optical axis direction inside the straight key barrel 8.

The above-mentioned spring 26 is suspended between the pin 22b of each barrier piece 22 and the locking piece 24c of the barrier drive ring 24, and moves each barrier piece 22 around the axis 23b in FIGS. In the clockwise direction, that is, in the closing direction,
Further, the spring 25 is suspended between a locking pin 23c erected on the barrier substrate 23 and a locking piece 24b of the barrier driving ring 24, and connects the barrier driving ring 24 to the springs 26,26. It is urged clockwise in FIGS. 7 and 8 against the urging force.

When the barrier drive ring 24 is locked to the clockwise rotation end shown in FIG. 7 by the urging force of the spring 25, the edge of each projection 24a of the barrier drive ring 24 is 5 against the pin 22b of each of them, pivoting each barrier piece 22 counterclockwise around the axis 23b against the biasing force of the spring 26, whereby the barrier pieces 22, 22 are opened as shown in FIG. Held in position. In addition, the barrier drive ring 24 having the projection 24d
Is rotated counterclockwise against the urging force of the spring 25, and is locked at the counterclockwise rotation end shown in FIG. To release the pin 22b, each barrier piece 22 pivots about the axis 23b counterclockwise in FIGS. 5 and 6 by the biasing force of the spring 26 and is held in the closed position shown in FIG.

On the other hand, on the inner peripheral surface of the rotary cylinder 6 in which a helicoid 62 screwed with the helicoid 51 of the movable cylinder 5 and a cam groove 63 for driving the rear lens group are further shown in FIG. Is formed between adjacent linear helicoids 62, 62, as shown in FIG.
And are formed in parallel. The upper right end (rear end) 65a of the cam groove 65 extending from the lower left to the upper right in FIG.
Is bent so as to have a shallow inclination with respect to a plane perpendicular to the optical axis. This bending point corresponds to the wide end shown in FIG. A cam pin (cam follower) 12 a protruding from the rear end of the operating lever 12 movably arranged in the optical axis direction inside the movable cylinder 5 is engaged with the cam groove 65.

On the top of the barrier drive ring 24,
As shown in FIG. 10, a short protruding piece 24d extending rearward is formed, and the protruding piece 24d extends in a direction substantially perpendicular to the cam groove 65 of the rotary cylinder 6, that is, from the upper left to the lower right in FIG. The cam groove 24e is formed to extend toward the center. A cam pin (cam follower) 12b projecting from the rear end of the operating lever 12 is engaged with the cam groove 24e.

FIGS. 11A and 11B are explanatory diagrams of the operation of the operating lever 12 in the barrier opening / closing mechanism having the above-described configuration.

Since the cam groove 65 formed in the rotary cylinder 6 is parallel to the helicoid 62 for driving the movable cylinder 5 in the range from the telephoto end to the wide end, the rotary cylinder 6 is moved from the telephoto end shown in FIG. When the motor is rotationally driven downward in FIG. 11 toward the wide end shown in FIG. 3, the cam pin 12a of the operating lever 12 moves rightward in the figure at a speed proportional to the rotation speed of the rotary cylinder 6. Since the barrier drive ring 24 held at 5 also moves to the right in the drawing at the same speed, the relative position between the barrier drive ring 24 and the operating lever 12 remains unchanged up to the wide end.

Next, when the engaging pin 12a enters the shallow portion 65a of the cam groove 65, the moving barrel 5 and thus the barrier drive ring 24 are still moved at a speed proportional to the rotating speed of the rotating barrel 6 to the right in the figure. However, since the moving speed of the cam pin 12a becomes slow, the operating lever 12 is pushed to the left in the drawing, whereby the cam pin 12b at the left end of the operating lever 12 is moved to the left relative to the barrier drive ring 24. 11B, the barrier drive ring 24 rotates downward in the figure by the action of the cam groove 24e forming an inclined surface, and when the rotary cylinder 6 rotates to the retracted position, as shown in FIG. The cam pin 12a reaches the tip of the shallow portion 65a of the cam groove 65, the cam pin 12b reaches the upper left end of the cam groove 24e, and the lens barrier is held at the closed position. On the contrary, after the rotary cylinder 6 is rotated from the retracted position to the telephoto end, the lens barrier is held at the open position.

As apparent from the above description, in the present embodiment, the driving cam groove 65 of the operating lever 12 for rotating the barrier driving ring 24 is formed on the inner peripheral surface of the rotary cylinder 6. In addition, it is easy to form the cam groove 65.

As the rotary cylinder 6 rotates between the wide end and the retracted position, the operation lever 12 is moved in the optical axis direction, and the movement of the operation lever 12 causes the barrier drive ring 24 to move. Since it is configured to rotate, the barrier pieces 22, 22 can be opened and closed smoothly and reliably.

Since the cam pins 12a and 12b are always engaged with the cam grooves 65 and 24e, respectively, the opening / closing operation of the lens barrier is stabilized, and the barrier drive ring 24
May be omitted in order to bias the spring 25 in the barrier opening direction.

The connecting means between the operating lever 12 and the barrier drive ring 24 is replaced by, for example, a slope 12c formed on the operating lever 12 side as shown in FIG. 12, instead of the cam pin 12b and the cam groove 24e shown in FIG. Barrier drive ring 2
A configuration may be employed in which the projections 24d on the fourth side are engaged, but in this case, a spring 25 for urging the barrier drive ring 24 in the barrier opening direction is required.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a zoom lens barrel provided with an embodiment of a barrier opening / closing mechanism according to the present invention.

FIG. 2 is a longitudinal sectional view taken along a vertical plane including an optical axis when the lens barrel in FIG. 1 is in a collapsed state;

FIG. 3 is a longitudinal sectional view taken along a vertical plane including an optical axis when the lens barrel in FIG. 1 is in a wide-angle shooting state;

FIG. 4 is a longitudinal sectional view taken along a vertical plane including an optical axis when the lens barrel in FIG. 1 is in a telephoto shooting state;

FIG. 5 is a schematic front view of a lens barrier unit when a barrier piece is in an open state.

FIG. 6 is a schematic front view of the lens barrier unit when the barrier piece is in a closed state.

FIG. 7 is a schematic rear view of the lens barrier unit corresponding to FIG. 5;

FIG. 8 is a schematic rear view of the lens barrier unit corresponding to FIG. 6;

FIG. 9 is a developed view showing a mechanism for rotating a barrier drive ring.

FIG. 10 is an exploded perspective view showing a configuration of a connecting portion between an operation lever and a barrier drive ring.

FIG. 11 is an explanatory diagram showing an operation when the lens barrel is retracted from a photographable state to a collapsed state.

FIG. 12 is an exploded perspective view showing a deformation of a connecting portion between the operation lever and the barrier drive ring.

[Explanation of symbols]

 Reference Signs List 1 lens barrel 12 operating lever 12a, 12b cam pin 2 lens barrier section 22 barrier piece 23 barrier substrate 24 barrier drive ring 24e cam groove 3 front group lens 4 shutter block 5 moving cylinder 6 rotating cylinder 62 helicoid 63, 65 cam groove 7 rear Group lens 71 Rear group lens holder 72 Cam pin 8 Straight key cylinder 81, 82 Guide groove 9 Fixed cylinder 10 Key plate

Claims (1)

[Claims] 1. A lens barrel comprising: a rotating barrel rotatable around an optical axis, the lens barrel being capable of extending and retracting a lens barrel with respect to a camera body by rotation of the rotating barrel; and a tip of the lens barrel. A lens barrier disposed to open and close the lens opening, and disposed in the lens barrel so as to be rotatable around an optical axis;
A camera provided with a barrier drive ring that opens and closes the lens barrier by the rotation thereof, comprising: a cam groove provided in the rotary cylinder; and a cam follower engaged with the cam groove. A barrier opening / closing mechanism, comprising: an operation lever that moves in the optical axis direction along with rotation of the rotary cylinder near a position to rotate a barrier drive ring.