JPH0214004Y2 - - Google Patents

Description

[Detailed explanation of the invention] (Technical field of the invention) This invention is based on autofocus (hereinafter referred to as AF)
This invention relates to a lens drive mechanism in a camera with functions.

(Background of the idea) In general, in cameras equipped with an AF function, the distance measuring device is activated by pressing the shutter button.
Next, the excitation ring of the lens barrel is rotated by excitation of the electromagnetic means, and the AF front plate that performs the shutter release is moved. When the lens barrel reaches the in-focus position, the electromagnetic means is activated. The excitation is removed to hold the payout ring in place.

FIGS. 1 and 2 show such a conventional lens drive mechanism. In the figure, 1 is a substrate, and 2 is a base substrate for a lens drive mechanism attached to the top surface of the substrate 1. It has an aperture 2a concentric with the photographing optical axis O approximately in the center, and the aperture 2a is A plurality of pillars 2b are planted around it. Reference numeral 3 denotes a lens feeding ring which is fitted into a stepped portion 2a' provided on the upper periphery of the opening 2a of the base substrate 2 so as to be rotatable about the optical axis O. a plurality of cam portions 3a whose heights are sloped so as to increase (counterclockwise in FIG. 1) and protrude upward on the same circumference of the upper surface of the feeding ring 3; A gear portion 3 in which the ratchet teeth 3b provided on the outer circumferential surface of the gear portion 3 can mesh with the gear 4 pivotally attached to the base substrate 2.
c and a pin 3d provided on the lower surface of the front plate so that it can be engaged with a protruding part of the front running plate for AF (autofocus), which will be described later. Has been given a habit. Reference numeral 6 denotes a lens barrel for supporting the lens, which is arranged concentrically with the feeding ring 3 and has the same number of engaging parts protruding in the radial direction as the number of cam parts 3a of the feeding ring 3. It is in contact with the cam portion 3a. Reference numeral 7 denotes a leaf spring integrally molded as an insert around the upper end region of the lens barrel 6, and includes a plurality of leaf springs for pressing the engaging portion of the lens barrel 6 against the cam portion 3a of the feeding ring 3. Spring part 7
a, a plurality of hook portions 7b that can be engaged with the engaging portion 8a of the front group frame 8 for holding down the front group lens, and a plurality of attachment portions provided on the outer periphery of the hook portions 7b.

9 is a guide pin 1 implanted in the base board 2
The AF front running plate is attached to the hook portion 9a, the protruding portion 9b that engages with the governor mechanism 12, and the pin 3d of the feeding ring 3. A protrusion 9c that engages with the spring 5 to prevent the feeding ring 3 from rotating to the left, and a spring 17
However, this leftward movement is delayed by the action of the governor mechanism 12. Reference numeral 13 denotes an electromagnetic plunger; 13a denotes a plunger that is given sliding properties and is pushed out from the electromagnetic plunger 13 by the tension of a spring 13b; 14;
is a drive plate pivotally attached to a pin connected to the plunger 13a, and the electromagnetic plunger 1 is attached to the other end.
A pawl portion 14a is provided which can engage with the ratchet teeth 3b of the feeding ring 3 in the non-energized state (the illustrated position) of the electromagnetic plunger 13, but separates from the feeding ring 3 when the electromagnetic plunger 13 is energized. Reference numeral 15 denotes a locking lever which is pivotally connected to the pin 11 and has a right-handed rotation ability with respect to the drive plate 14 by a spring 16. When the pin 15a provided on the lower surface of the lever comes into contact with the drive plate 14, the lock lever 15 rotates to the right. is limited, and further includes a bent portion 15b that can engage with the hook portion 9a of the front running plate 9.
It is equipped with Note that FIG. 1 shows the set state, and the front running plate 9 is at its rightmost position when the locking lever 1 is engaged.
The bent portion 15a of the front running plate 9 is engaged with the hook portion 9a of the front running plate 9, and the feeding ring 3 is at its most right-handed position, so the lens barrel 6 is rotated as shown in FIG. It is at the position shown on the left, that is, at the near point of the lens.

In the above configuration, when the shutter button is pressed down, the electromagnetic plunger 13 is energized and the plunger 13a is attracted against the tension of the spring 13b, so that the drive plate 14 is rotated to the left and the claw portion 14a of the electromagnetic plunger 13 is attracted. is separated from the outer periphery of the feeding ring 3, and as the drive plate 14 rotates counterclockwise, the locking lever 1
5 is also rotated to the left when its pin 15a is pushed by the drive plate 14, and its bent portion 15b is disengaged from the hook portion 9a of the front running plate 9, so that the front running plate 9 is activated by the governor mechanism based on the tension of the spring 17. 12
The feed ring 3 moves to the left with a delay due to the engagement with the protrusion 9b, and at this time, the tension of the spring 5 causes the feed ring 3 to rotate to the left while its pin 3d follows the protrusion 9c of the front running plate 9. Tsute lens barrel 6
is moved downward from the position shown on the left side to the position shown on the right side in FIG. 2 based on the slope of the cam portion 3a of the feeding ring 3. When focus is detected by the AF function means (not shown), the electromagnetic plunger 13 is de-energized, the plunger 13a returns to the position shown in FIG. 1 by the tension of the spring 13b, and the drive plate 14 is moved to the right. As the claw portion 14a engages with the ratchet teeth 3b of the feeding ring 3,
The feeding ring 3 is prevented from rotating to the left and the lens barrel 6 is stopped, but the front running plate 9 continues to move to the left and reaches the leftmost position, where the shutter release is performed. There is.

However, in the above conventional configuration, in the initial state shown in the first diagram, the locking lever 15 has
The load of the spring 17 that biases the AF front running plate 9 and the spring 5 that applies a load to the AF front running plate 9 through the feeding ring 3 is high, and therefore the electromagnetic plunger 13 moves the locking lever 15 above. The electromagnetic plunger 1 must be moved against two springs, and in order to ensure the amount of force for releasing the locking lever 15, the electromagnetic plunger 1 must be moved against the force of two springs.
3 has increased, and the electromagnetic plunger 13 has also become larger to some extent. That is, in terms of space factor and power consumption, this is not a desirable mechanism to be built into a small camera.

(Objective of the Invention) Therefore, the object of the present invention is to solve the above-mentioned conventional drawbacks, reduce the operating force of the electromagnetic means, and reduce the size and power consumption of the electromagnetic means.

(Summary of the invention) In order to achieve the above object, the present invention prevents the movement of the AF front running plate in the initial position, and also prevents the sliding of the AF front running plate by moving by the initial rotation of the feeding ring. A general feature is the provision of a locking lever that allows forward running.

(Embodiment of the invention) Fig. 3 is a plan view of the main parts of a lens drive mechanism according to an embodiment of the invention, and parts that are the same or equivalent to the conventional structure described above are given the same reference numerals, and details thereof are omitted. .

In the figure, 9d is a rack provided on the lower right side of the AF front running plate 9 in the illustration, and is a rack provided on the gear body 1 of the governor mechanism 12.
It meshes with 2a. Reference numeral 20 denotes a forward locking lever which is pivotally supported by the guide pin 10, and is applied with a rotational force in the left rotation direction in the drawing around the guide pin 10 by a spring 21, and in the initial state shown in the drawing, one end of the locking lever is The bent piece 20a is engaged with the hook portion 9a of the AF front running plate 9 to prevent the front running plate 9 from moving, and the driven portion 20b at the other end is brought into contact with the outer peripheral surface of the feeding ring 3. I'm letting you do it. 22 is a stopper of the forward travel locking lever 20.

23 is the plunger 1 of the electromagnetic plunger 13
3a, and the other end is pivotally supported by the guide pin 11. When the electromagnetic plunger 13 is in a non-excited state, it is pushed to the illustrated position by the spring 13b of the electromagnetic plunger 13. It's been raised. Reference numeral 24 denotes a feed-out locking lever that is pivotally supported by the guide pin 11, and a protrusion 24a at one end thereof is loosely fitted into a hole 23a of the drive plate 23, and the protrusion 24a is supported by an appropriate spring means (not shown). The lever 24 is biased in an upward direction, and the lever 24 moves together with the drive plate 23. 24b and 24c are the feeding locking levers 2
In the initial state shown in the figure, the locking part 24b comes into contact with the stopper part 3e of the feeding ring 3 and prevents the rotation of the feeding ring 3. There is.

25 is a spring charge lever that is pivotally supported on the guide pin 11; 26 is wound around the guide pin 11; one end thereof is attached to the bent piece 23b of the drive plate 23; the other end is attached to the protrusion 25a of the spring charge lever 25. The respective locked springs apply a turning force to the spring charge lever 25 in the counterclockwise direction as shown in the figure, and in the initial state shown in the figure, the spring charge lever 25 has its protrusion 25a attached to the bent piece 23b. While being in contact with each other, the arm portion 25b is spaced apart from the outer periphery of the feeding ring 3 by a predetermined amount.

In the above configuration, when the electromagnetic plunger 13 is excited from the initial state shown in FIG. 1 and the plunger 13a is attracted (moved downward in the figure), the drive plate 23 and the feeding locking lever 24 connected thereto are rotated in the counterclockwise direction. As a result, the locking portion 24b of the feeding locking lever 24 is released from the stopper portion 3e of the feeding ring 3. Further, as the drive plate 23 rotates, the spring charge lever 25 also rotates in the counterclockwise direction in the figure, and the tip of the arm 25b abuts the recess 3e on the outer circumference of the feeding ring 3. reach the position.

Due to the above operation, the feeding ring 3 is released from the locking lever 24 by the spring 5.
The initial rotation causes the protrusion 3f to push the driven portion 20b that is in contact with the outer periphery of the driven portion 20b, causing the forward running locking lever 20 to rotate in the clockwise direction as shown in the figure. The bent piece 20a of the front running locking lever 20 is separated from the hook portion 9a of the AF front running plate 9. Therefore, the AF front running plate 9, which has been released from the mooring by the front running locking lever 20, also begins to slide to the left in the figure due to the force of the spring 17, and the governor mechanism 1
After engaging the pin 3d with the protrusion 9c of the AF front running plate 9, which moves while being decelerated by the AF
The front running plate 9 and the feeding ring 3 slide and rotate at the same speed. During this time, the spring charge lever 25, which has the arm portion 25b in contact with the recess 3e on the outer periphery of the feeding ring 3, pushes the arm portion 25b upward onto the outer periphery in the clockwise rotation direction in the drawing against the spring 26. The spring 2 is rotated by the feeding ring 3 as shown in FIG.
6 spring force is accumulated. (The protrusion 25a is separated from the bent piece 23b to perform spring charging in the direction of driving the drive plate 24 in the clockwise rotation direction.) Then, the lens barrel, which moves with the rotation of the feeding ring 3, is brought into focus. When it is detected that the electromagnetic plunger 13 has reached the position, the excitation of the electromagnetic plunger 13 is cut off based on this coincidence detection signal, and the drive plate 23 and the feeding locking lever 24 are activated by the spring 13b of the electromagnetic plunger 13 and the above operation. Due to the accumulated force of both springs 26, the spring 26 quickly returns to the position shown in the first diagram. By this return, the claw portion 24c of the feeding locking lever 24 meshes with the ratchet teeth 3b of the feeding ring 3, and the feeding ring 3, that is, the lens barrel is positioned. Then, as in the conventional example described above, only the AF front travel plate 9 moves to the final position, and the shutter release is performed. After the shutter release, the automatic exposure control means closes the shutter in an appropriate time to complete the shooting, and the AF front travel plate 9 is returned to the right side in the figure in conjunction with the film winding mechanism. In other words, all the members return to the state shown in the third figure.

(Effects of the invention) As detailed above, according to the invention, the AF front running plate is moored at the initial position by the front running locking lever, and the rotation of the feeding ring at the initial position is prevented by the feeding locking lever. The electromagnetic plunger (electromagnetic means) first moves only the feeding locking lever to rotate the feeding ring, and the initial rotation of the feeding ring causes the front running lock to move. This type of camera has a configuration in which the locking lever is driven to unmoor the AF front running plate, so the operating force of the electromagnetic means can be reduced compared to conventional cameras, making it possible to downsize the electromagnetic means and reduce power consumption. This provides great practical effects in lens drive mechanisms for use in other applications.

[Brief explanation of the drawing]

1 and 2 relate to a conventional lens drive mechanism, FIG. 1 is a plan view of the main part, FIG. 2 is a sectional view of the main part, and FIG. 3 is a lens drive mechanism according to an embodiment of the present invention. FIG. 3... Feeding ring, 5... Spring, 6... Lens barrel, 9... AF front running plate, 12... Governor mechanism, 13... Electromagnetic plunger (electromagnetic means), 17
. . . Spring, 20 .

Claims (1)

[Scope of utility model registration request] A lens barrel unit that supports the lens, a feeding ring that supports the lens barrel unit and moves the lens barrel unit for focus adjustment according to the rotation thereof, and a rotating force applied to the feeding ring in a certain direction. a first spring that applies a first spring; a drive plate that is actuated by the excitation of the electromagnetic means; and a first spring that is engaged with the drive plate and that prevents rotation of the feeding ring when the electromagnetic means is not energized to initialize the feeding ring. A feed-out locking lever is held in position and moved by the excitation of the electromagnetic means to allow rotation of the feed ring, and a lever is slidably held in order to release the shutter and is made to follow its constant speed movement. an autofocus front running plate that brings the feeding ring to the focusing position; a second spring that applies a biasing force to the autofocus front running plate in the shutter release direction;
Before the movement of the autofocus front plate, which is at the initial position opposite to the shutter release direction, is prevented, and the autofocus front plate is moved by the initial rotation of the feeding ring, and the autofocus front plate is allowed to slide. A lens drive mechanism characterized by comprising a travel locking lever.