JPH0572601A - Lens shutter driving mechanism used also as lens driving mechanism - Google Patents

Abstract

PURPOSE:To improve a mechanism for driving a lens and a shutter blade where a step motor is used as a driving source. CONSTITUTION:When a main driving member 4 connected to the motor 1 is rotated counterclockwise, a lens driving member 5 connected to the lens is rotated counterclockwise in a state where its step part 5d is engaged with a pin 4a. At such a time, a recessed cam 4g passes a cam follower 7b, and the clockwise rotation of the cam follower 7b is regulated by the cam edge 5f of the member 5, and the clockwise rotation thereof is regulated by the cam edge 4f after the member 5 is rotated counterclockwise. When the member 4 is rotated clockwise by engaging with a ratchet 5a at a focusing position, the cam follower 7b is released from the cm edge 5f at such a time, so that the cam follower 7b falls in the recessed cam 4g from a cam edge 4f, and an opening and closing member 7 is rotated clockwise. Therefore, the opening and closing lever 7 is actuated only in the case of the initial restoration of a main driving member even when a one-way clutch is not provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lens shutter drive mechanism that also serves as a lens drive mechanism, and more specifically, to sequentially drive the lens drive mechanism and the shutter drive mechanism using a single step motor as a drive source. The present invention relates to a lens shutter drive mechanism that also serves as the lens drive mechanism.

[0002]

2. Description of the Related Art In photographing with a still camera, a shutter mechanism is operated after positioning a lens mechanism. Therefore, when a single motor is also used as the drive source for the lens drive mechanism and the shutter drive mechanism, the lens drive member is moved to the in-focus position by the main drive member geared to the motor when the motor rotates in one direction. After positioning, the motor is reversed and the blade drive member connected to the shutter blade is opened and closed in the process of returning the main drive member to the initial position.

For example, in FIG. 3, when the main drive ring 4 connected to the output pinion 2 of the step motor 1 via the two-step gear 3 rotates counterclockwise, the lens drive ring 5 connected to the lens group (not shown) is stepped. The portion 5d is engaged with the pin 4a, rotates counterclockwise, and is driven to the in-focus position. When the step motor 1 is reversed at the in-focus position, the ratchet gear 5a formed on the lens drive ring 5 is engaged with the ratchet lever 6 and only the main drive ring 4 rotates rightward to return to the initial position. The opening / closing lever 7 connected to the shutter blades when the main drive ring 4 is returned to the cam 4b of the main drive ring 4.
The aperture is released and the exposure operation is performed.

[0004]

In the case of the above-mentioned mechanism, the cam 4b of the main drive ring 4 passes through the opening / closing lever 7 both in forward rotation and in reverse rotation. However, since the opening / closing lever 7 is not allowed to operate until the positioning of the lens drive ring 5 is completed, the cam 4b is rotated only when the main drive ring 4 is rotated counterclockwise.
Therefore, it is necessary to interpose a one-way clutch mechanism or the like so that the switch acts on the opening / closing lever 7. For example, Figure 3
A clutch lever 10 is pivotally supported on a shaft 9a on a locking lever 9 which is pivotally supported on a shaft 8 for locking the opening / closing lever 7. The clutch lever 10 independently turns right around the shaft 9a when passing through the point of the position of the clutch lever 10, and when the cam 4b passes the position of the clutch lever 10 when turning of the main drive ring 4 to the right, the clutch lever 10 moves toward the engaging lever 8 of the clutch lever 10. At the same time, the opening / closing lever 7 is unlocked by turning counterclockwise around the shaft 9.

Therefore, many members such as locking levers and clutch levers must be housed in a narrow space around the shutter, which causes problems such as deterioration of space efficiency and increase of manufacturing cost, and further There is a problem that an exposure timing error occurs due to a member error.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve such problems, and provides a lens drive mechanism and a shutter mechanism without providing a locking lever, a one-way clutch mechanism, or other related mechanisms. It is an object of the present invention to provide a lens shutter drive mechanism that also serves as a lens drive mechanism that is capable of sequence control.

In summary, a lens shutter drive mechanism of the present invention which also serves as a lens drive mechanism includes a step motor capable of rotating in the forward and reverse directions: a main drive member which is connected to the step motor and travels in the forward or reverse direction. : A lens driving member that drives the lens group by following the main driving member when the main driving member travels in the forward direction; and: engages the lens driving member when the main driving member reverses from the forward traveling to the backward traveling. And a blade driving member connected to a shutter blade that opens and closes the exposure opening, respectively: sequentially opens and closes the opening of the blade driving member while the main driving member is running in the reverse direction. On the premise of a lens shutter drive mechanism that also serves as a lens drive mechanism, the main drive member is formed with a first cam edge for opening and closing the blade drive member: A second member for restricting the operation of the blade driving member at its initial position and releasing the operation restriction of the blade driving member before driving the lens group to a predetermined position when the member travels in the forward direction. Forming a cam edge: so that the main driving member follows the lens driving member after the first cam edge passes through the cam sliding portion of the blade opening / closing member when the main driving member travels in the forward direction. It is characterized by having done.

[0008]

That is, according to the lens shutter drive mechanism of the present invention which also serves as the lens drive mechanism, the lens is moved after the first cam edge passes through the cam sliding portion of the blade opening / closing member when the main drive member is operated in the forward direction. The driving member is normally rotated by being engaged with the main driving member. That is, even when the main drive member is normally rotated from the initial position, the first cam edge passes through the cam sliding portion of the blade opening / closing member, but at this time, the lens drive member is in the initial position and the lens drive member is in the initial position. The second cam edge formed on the lens driving member restricts the operation of the blade opening / closing member when the position is at, and thus the blade opening / closing member remains closed. After driving the lens driving member to the in-focus position, the main driving member returns to the initial position, and at this point, the second cam edge formed on the lens driving member is retracted, so that the main driving member returns to the initial position. In the process, the first cam edge drives the blade drive member to open and close.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings. 1 shows the drive mechanism of the present invention, and
FIG. 2 shows a blade peripheral mechanism. The output pinion 2 of the step motor 1 meshes with the rack 4c formed on the main drive ring 4 via the two-stage gear 3, and the main drive ring 4 forms the pinion 2 around the aperture AP (see FIG. 2). Rotate in the same direction.

The lens drive ring 5 is rotatably supported around the aperture AP.
The spring hook 5b projectingly formed on the outer edge of the spring 11b is used to return the initial position. (In order to avoid complication of the drawing, the biasing spring is shown only by the arrow in the drawing. ) Is applied to the lens driving ring 5 and the lens driving ring 5 is given a rightward turning property by the spring 11, but the stopper pin 5c is planted on the back surface of the spring hook 5b.
Comes into contact with a stopper member (not shown) formed on the shutter base plate BP (see FIG. 2), and right rotation is restricted at the position shown in FIG.

A pin 4a for engaging the lens drive ring 5 is planted in the main drive ring 4, and a step 5d engaged with the pin 4a is formed on the outer edge of the lens drive ring 5. ing. Three convex cams 5e are formed at 120-degree intervals on the front side surface (lens side surface) of the lens drive ring 5, and the three-point convex cams 5e are mirrors in which a focusing lens group (not shown) is inserted. Three inclined cam surfaces of the same shape formed on the film surface side of the barrel are in contact with each other. The lens barrel (not shown) is restricted by, for example, a guide groove or a guide pole so as not to make a turning motion.
When is rotated, the focusing lens group (not shown) is extended in the optical axis direction.

Further, a ratchet gear 5a for positioning the lens drive ring 5 itself is formed on the outer edge portion of the lens drive ring 5, and a ratchet gear 5a is provided on a shaft 12 provided outside the ratchet gear 5a. A ratchet lever 6 that engages 5a is rotatably supported.
The ratchet lever 6 has a click 6a for engaging with the ratchet gear 5a, and is always subjected to a left-handed habit from the spring 13, but in the initial state, the shelf 6c formed continuously with the cam surface 6b is bent. The spring 13 rides on the outer surface of the portion 4d and restricts leftward rotation by the spring 13.

Next, an opening / closing lever 7 for driving the shutter blades 14 to open and close is pivotally supported by a shaft 15, and the shutter blades 14 are swingably supported by a shaft 16 provided on a base plate BP. A blade drive pin 7a is planted on the back surface of the opening / closing lever 7, and the blade drive pin 7a is attached to the main plate BP.
Slot 14 formed through the shutter blade 14
engaged with a. Therefore, when the opening / closing lever 7 rotates clockwise around the shaft 15, the shutter blade 14 rotates clockwise around the shaft 16 to open the aperture AP for exposure. still,
In FIG. 1, a driving force for turning the opening / closing lever 7 to the right is given by a spring 17. Although only one shutter blade 14 is shown in the drawing, the aperture A
A shutter blade (not shown), which is basically symmetrical with the shutter blade 14, is provided with a line segment connecting the center of P and the center of the blade drive pin 10a as a target axis.

As described above, the opening / closing lever 7 has the spring 17
A right turning force is applied from the cam edge 4 formed on the main drive ring 4 in the initial position as a characteristic point of this embodiment.
The right turning operation of the opening / closing lever 7 is restricted by e.
A concave cam 4g is formed between the cam edge 4e and a cam edge 4f that follows the cam edge 4e. When the concave cam 4g passes the position of the cam follower 7b of the opening / closing lever 7, the cam follower 7g is formed.
When "b" falls on the concave cam 4g, the opening / closing lever 7 moves to the spring 1
It is designed to turn right by the biasing force of 7.

On the other hand, the lens drive ring 4 is formed with a cam edge 5f which comes into contact with the cam follower 7b at the initial position and restricts the clockwise rotation of the opening / closing lever 7, and the cam edge 5f is retracted from the position of the cam follower 7b. Is a precondition for the opening / closing lever 7 to rotate clockwise. As a feature of this embodiment, the pin 4a for engaging the step portion 5d of the lens drive ring 5 is provided with the concave cam 4 when the main drive ring 4 is rotated counterclockwise.
After g passes through the cam follower 7b and the cam edge 4f enters the position of the cam follower 7b, the step portion 5d is engaged and the lens drive ring 5 is driven.

Next, the operation of this embodiment will be described with reference to the above matters. First, in a normal initial state, all the mechanisms are in the states shown in FIGS. 1 and 2, and when the output pinion 2 of the step motor 1 is turned counterclockwise from this state, the rotation of the pinion 2 passes through the two-stage gear 3 and the rack 4c. Is transmitted to the main drive ring 4 to rotate the main drive ring 4 counterclockwise.

When the main drive ring 4 rotates counterclockwise, the concave cam 4g formed on the outer edge of the main drive ring 4 passes through the position of the cam follower 7b of the opening / closing lever 7, but the lens drive ring 5 is at the initial position at this point. , Lens drive ring 5
The cam edge 5f formed on the outer edge of the abutment abuts on the cam follower 7b to regulate the right-hand rotation of the opening / closing lever 7. Therefore, the shutter blades 14 do not open at this point. The shelf 6c formed on the ratchet lever 6 by the left rotation of the main drive ring 4 has a bent portion 4c formed on the main drive ring 4.
The ratchet lever 6 is released from the outer surface of d and the ratchet lever 6 is rotated counterclockwise by the spring 13.

When the main drive ring 4 continues to rotate counterclockwise in this manner, the pin 4a planted in the main drive ring 4 engages the step portion 5d of the lens drive ring 5 to return the spring 1 for return.
The lens drive ring 5 is rotated counterclockwise against 1, and the cam follower 7b of the opening / closing lever 7 is moved to the cam edge 5 of the lens drive ring 5.
Although released from f, the main drive ring 4 has already been released at this point.
Since the cam edge 4f of is in contact with the cam follower 7b,
The open / close lever 7 does not rotate right.

The main drive ring 4 continues the left-handed motion while the lens drive ring 5 is driven, and the focus adjustment lens group (not shown) is extended as the lens drive ring 5 turns left. When the lens drive ring 5 is extended to the in-focus position, the motor driver (not shown) reverses the step motor 1, the output pinion 2 rotates right, and the main drive ring 4 also rotates right.

When the main drive ring 4 is turned clockwise, the step portion 5d of the lens drive ring 5 is released from the pin 4a of the main drive ring 4, but the ratchet gear 5a is engaged with the click 6a of the ratchet lever 6. The lens drive ring 5 stops at the in-focus position. Therefore, at this time, the opening / closing lever 7
The cam follower 7b is a cam edge 5f of the lens drive ring 5.
Will be released from.

Therefore, when the main drive ring 4 further turns right and the concave cam 4g reaches the position of the cam follower 7b, the cam follower 7b falls into the concave cam 4g and the opening / closing lever 7 is turned right by the spring 17. At this time, the control circuit (not shown) stops the stepping motor 1 for a time corresponding to the desired exposure time, and interrupts the clockwise rotation of the main drive ring 4.

When the opening / closing lever 7 is turned clockwise, the shutter blade 1
In slot 4, the slot 14a is engaged with the pin 7a, and the slot 14a is rotated clockwise about the shaft 16 to open the exposure aperture AP.
Then, when the step motor 1 restarts the clockwise rotation after the time corresponding to the desired exposure time elapses, the main drive ring 4
Restarts the clockwise rotation, and the sloped portion of the concave cam 4g pushes up the cam follower of the opening / closing lever 7 and rotates the opening / closing lever 7 counterclockwise against the spring 17.

The shutter blade 14 rotates counterclockwise around the shaft 16 as the opening / closing lever 7 rotates counterclockwise, and the exposure aperture AP.
And the exposure operation ends. Then, in the process in which the main drive ring 4 is rotated rightward to the initial position, the bent portion 4b of the main drive ring 4 moves from the cam edge 6b of the ratchet lever 6 to the shelf 6c.
When it goes up to, the ratchet lever 6 turns right against the spring 13 and releases the ratchet gear 5a. Therefore, the lens driving ring 5 is also returned to the initial position by the spring 11, and one photographing operation is completed.

In the above description, the example in which the stepper motor is used as the drive source to drive the program shutter that also serves as the diaphragm blade is shown. However, the present invention is not limited to the lens shutter even when the diaphragm blade is provided alone. Widely applicable if there is. Also, in the above, an example in which the main driving member and the lens driving member are formed in the shape of a ring that rotates around the aperture has been shown, but these may be made to perform linear movement.
Furthermore, in the above, an example in which the lens driving member drives the focus adjusting lens group has been shown, but the present invention can also be applied to, for example, a zoom lens group for zooming.

[0025]

As described above, in the case of the present invention, the shutter blades are arranged corresponding to the positions of the main driving member gear-connected to the motor and the lens driving member that drives the lens by following the main driving member. Since the opening / closing operation of the opening / closing lever for driving is performed, it is not necessary to provide an auxiliary mechanism such as a one-way clutch for operating the opening / closing lever, and the mechanism around the shutter can be simplified.

Further, according to the present invention, the operation timing of the opening / closing lever is directly controlled by the rotation of the step motor, and on the other hand, there is no intervening clutch or the like, so that it is unlikely to be affected by rattling or play of mechanical members or mounting error. The control accuracy is extremely improved.

[Brief description of drawings]

FIG. 1 is a plan view of a mechanism according to an embodiment of the present invention in an initial state.

FIG. 2 is a plan view around the shutter blade of the mechanism according to the first embodiment of the present invention.

FIG. 3 is a plan view of the conventional seed mechanism in an initial state.

[Explanation of symbols]

 1 step motor 2 pinion 4 main drive ring 4a pin 4e cam edge 4f cam edge 4g concave cam 5 lens drive ring 5d step 5f cam edge 6 ratchet lever 7 open / close lever 14 shutter blade

Claims (1)

[Claims] 1. A forward / reverse rotatable step motor, a main drive member that is connected to the step motor and travels in a forward or reverse direction, and a main drive member that follows the main drive member when the main drive member travels in the forward direction. Lens drive member for driving the lens group by
An engaging member that engages the lens driving member when the main driving member reverses from the forward traveling to the backward traveling; and a blade driving member that is connected to a shutter blade that opens and closes the exposure opening. In a lens shutter drive mechanism that also serves as a lens drive mechanism for sequentially performing opening release and closing drive of the blade drive member in the course of traveling of the main drive member in the reverse direction, the blade drive member is opened and closed with respect to the main drive member. Before forming a first cam edge for driving, restricting the operation of the blade driving member at the initial position of the lens driving member, and driving the lens group to a predetermined position when the lens driving member travels in the forward direction. Is formed with a second cam edge for releasing the regulation of operation of the blade drive member, and the first cam edge causes the cam slide point of the blade opening / closing member when the main drive member travels in the forward direction. Lens shutter driving mechanism main drive member after passing is also serves as a lens driving mechanism, characterized in that the manner is driven the lens driving member.