JPH0550437U - Aperture control device - Google Patents

Abstract

(57) [Summary] [Purpose] When the interchangeable lens is attached, eliminate the risk of damage to the gear train including the speed reduction mechanism. [Structure] A setting member 4 for setting an aperture position is driven to a setting position by a stepping motor 8 via speed reduction mechanisms 5 and 6 before an image capturing operation. It receives the force applied when it comes into pressure contact and stops so that it is not transmitted to the stepping motor. When the diaphragm lever 19 contacts the diaphragm interlocking lever 2, there is a gap with the diaphragm interlocking lever in the open position.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an aperture control device provided in a camera with interchangeable lenses.

[0002]

[Prior Art]

 As a diaphragm control device that uses a setting member to set the position taken by the diaphragm interlocking lever (camera body side) that interlocks with the diaphragm lever (interchangeable lens side) that opens and closes the aperture opening, the reverse rotation prevention function There is one that sets the setting member via a deceleration mechanism including the. In this device, by supporting the force from the output side by the reverse rotation prevention function, the setting member can be continuously set to the setting position even if the driving force of the setting member is released.

[0003]

[Problems to be solved by the device]

 However, the above-described conventional aperture control device has the following problems because the aperture interlocking lever and the setting member are in contact with each other even before the aperture setting operation. First, it is impossible in manufacturing to set the open limit positions of all interchangeable lenses to the same position, and each interchangeable lens has its own open limit position. Therefore, if the lens is exchanged while the aperture lever is in contact, and the open limit position of the lens after exchange is closer to the aperture side than before exchange, the aperture interlocking lever has a reverse rotation prevention function. , A large amount of force is applied between the aperture lever and the aperture interlocking lever.

At this time, since the force of the aperture lever pushing the aperture interlocking lever is stronger than the force of the speed reduction mechanism that tries to stop the setting member at the set position, the aperture interlocking lever is pushed by the aperture lever. It will be. As a result, the setting member that is in contact with the aperture interlocking lever is also moved to the position narrowed down from the position maintained by the speed reduction mechanism. Therefore, a large load is applied to the gear train of the drive unit including the speed reduction mechanism, which may damage the gear train. If the gear train is damaged, the subsequent setting operation of the setting member to the moving position cannot be accurately controlled.

A first object of the present invention is that when the interchangeable lens is attached, the setting member is not moved from the position maintained by the reduction mechanism, and the gear train including the reduction mechanism is damaged. An object is to provide a diaphragm control device without fear. The second object of the present invention is to set the aperture limit position of the interchangeable lens, which is peculiar to the aperture limit, to the aperture position, and to perform accurate aperture control based on the aperture position during shooting operation. To provide a device.

[0006]

[Means for Solving the Problems]

 In order to solve the above problems, an aperture control device according to the present invention is an aperture control device provided in a camera to which an interchangeable lens having an aperture and an aperture lever (19) for opening and closing the aperture is attached and detached. And an aperture interlocking lever (2) which engages with the aperture lever to determine the position of the aperture lever, and a setting means (4) which is engageable with the aperture interlocking lever and sets the position of the aperture interlocking lever. ) And the setting means is movable between an initial position taken at the beginning of shooting start and a moving position taken at the time of shooting moved in one direction from the initial position, and the aperture interlocking lever is The setting means in the initial position positions it in the open position, and the setting means moves in the open position to the setting position in the moving position. Open In the aperture control device, the aperture is fully opened when it is in the stationary position, and when the aperture interlocking lever is in the previously set position, the aperture is narrowed down from the fully open condition. The deceleration mechanism cannot substantially displace even if an external force is applied from the diaphragm drive lever, and the diaphragm lever comes into contact with the diaphragm interlocking lever. By being positioned at the retracted position moved from the position in the one direction, it has a gap with the aperture interlocking lever in the open position, which prevents the external force from being applied from the aperture interlocking lever. To do.

In this case, the setting means has a detection means for detecting that the setting means is in the initial position, and during the photographing operation, the setting means moves from the retracted position to the initial position in a direction opposite to the one direction. It can be characterized in that it moves in one direction, and when it receives an output from the detection means, it moves in one direction to the moving position.

Further, the setting means includes a stepping motor (8), and the control setting position is a position narrowed by at least one step of the stepping motor from the control opening position. it can. Further, the reduction mechanism may be characterized by including a worm (5) and a worm wheel (6).

[0009]

[Action]

 In the present invention, when the interchangeable lens is completely attached, it is positioned at the retracted position which is moved in one direction from the initial position, so that a gap is provided between the setting member and the aperture interlocking lever at the open position. Even if an interchangeable lens having an open limit position is attached, there is no risk of damaging the gear train of the reduction mechanism.

Further, during the image pickup operation, the setting means is moved to the moving position after being moved to the initial position. Therefore, the opening limit position peculiar to the interchangeable lens is set to the opening position of the diaphragm aperture, and the opening position is set to the opening limit position. The setting means can be accurately positioned at the movement position taken at the time of shooting with the reference as a reference.

[0011]

【Example】

 Hereinafter, embodiments will be described in more detail with reference to the drawings and the like. FIG. 1 is a perspective view showing an embodiment of a diaphragm control device according to the present invention. First, the mechanical portion of the aperture control device of this embodiment will be described. The diaphragm lever 19 is a member that is provided on the side of the taking lens and determines the diaphragm aperture, and is biased in the diaphragm direction (downward in FIG. 1).

The aperture interlocking lever 2 is rotatably attached to a frame plate 1 such as a mirror box by a shaft 9. In this diaphragm interlocking lever 2, a key portion 2b formed at the tip of an arm portion 2a is engaged with a diaphragm lever 19, and a contact portion 11 is provided on a pin portion 2c of the arm portion 2a.

The aperture charge lever 3 is a bell crank-shaped member having two arm portions 3b and 3c, and is rotatably attached to the frame plate 1 by a shaft 9. A spring hooking portion 3a is bent and raised on the arm portion 3b, and is biased counterclockwise in FIG. 1 by an aperture charge spring 10 hooked between the arm hooking portion 3a and the spring hooking portion 1a of the frame plate 1. .. Moreover, a key portion 3d is provided at the tip of the arm portion 3c, and is engaged with the arm portion 2a of the diaphragm interlocking lever 2.

In the aperture setting member 4, a fan-shaped main body 4 a is rotatably attached to the frame plate 1 by a shaft 9. A gear 4b is provided on the circumference of the fan-shaped main body 4a, and an arm 4c is engaged with a pin 2c of the diaphragm interlocking lever 2.

The gear 4 b of the aperture setting member 4 meshes with the worm wheel 5, and the worm wheel 5 meshes with the worm 6. The worm 6 meshes with a motor gear 7 provided on the output shaft of the stepping motor 8.

The aperture charge spring 10 is charged by the aperture charge mechanism, and its urging force drives the aperture lever 19 via the aperture charge lever 3 and the aperture interlocking lever 2 to charge the aperture drive spring in the photographing lens. To do.

The non-conductive member 11 A is a member for insulating the conductive member 11 B from the diaphragm interlocking lever 2. As shown in FIG. 12 (B), the non-conducting member 11A has two cylindrical members 11A ₁ facing each other as shown in FIG. 12 (C). As described above, the cylindrical conductive member 11B is sandwiched. The shaft 2c is fixed to the squeezing interlocking lever 2 by caulking or the like. The center hole of the non-conducting member 11A is inserted into the shaft 2c, and the E-ring 2e is inserted into the tip side to prevent the shaft 2c from coming off. .

The open position detection switch 12 is electrically connected to the frame plate 1 via the conduction member 15. Since this open position detection switch 12 is a leaf spring, it is always urged in the direction of the arrow in FIG. 1, and when it is near the aperture opening (near the one shown in FIG. 1), the open position detection switch 12 is , Is in contact with the conducting member 11B. The conduction member 11B is in contact with the arm 4c of the diaphragm setting member 4. In the open position detection switch 12, when the conductive member 11B comes into contact with the diaphragm setting member 4 while being in contact with the conductive member 11B, Vcc drops to the ground, and the diaphragm setting member 4 sets open. It detects that it is in the position.

The sequence lever 13 engages with the aperture charge lever 3 to charge the aperture charge spring 10. The limiting pin 14 is implanted in the frame plate 1, and the limiting pin 14 limits the position of the aperture charge lever 3 when the interchangeable lens is not attached to the camera body. When the interchangeable lens is mounted, the aperture position of the aperture interlocking lever 2 is determined by the aperture lever 19. At that time, a gap is always set between the aperture charge lever 3 and the limiting pin 14. The gap between the retracted position and the initial position of the aperture interlocking lever 2 is set to be wider than the range of variation of the limit open position of each interchangeable lens to be mounted. Since the aperture interlocking lever 2 is engaged with the aperture charge lever 3, even if an interchangeable lens having an aperture lever 19 having a different opening limit position is attached, the worm wheel 5 and the worm 6 arranged in the rear stage. There is no fear that the gear train of the deceleration mechanism will be damaged.

FIG. 2 is a control block diagram showing an embodiment of the diaphragm control device according to the present invention. The photometric element 22 is an element that measures reflected light from a subject, and its output is connected to the CPU 21 via a photometric circuit 23. Further, the CPU 21 is connected to the output of the open position detection switch 12 and the output of the half-push switch SW1 which is turned on when the release button is half-pushed and the full-push switch SW2 which is turned on when it is full-pushed.

The CPU 21 is a central processing unit that generates an aperture amount control signal based on the photometric value from the photometric circuit 23 and controls the entire camera. The output of the CPU 21 is connected to the stepping motor drive circuit 24, and the stepping motor drive circuit 24 drives the stepping motor 8 shown in FIG.

Next, the operation of the aperture control device of this embodiment will be described. 3 to 5 are flowcharts for explaining the operation of the CPU, and FIGS. 6 to 11 are explanatory diagrams showing the operation of the mechanical unit. When the half-push switch SW1 is turned on while the release button is half-pushed, the photometric circuit 23 starts photometry (step S31) and calculates the aperture value based on the photometric value (step S32). The interrupt enable state by the ON signal is set (step S33).

At this time, as shown in FIG. 6, the aperture interlocking lever 2 is kept in the aperture open position by the urging force of the aperture charge spring 10, and the aperture setting member 4 is spaced apart from the aperture interlocking lever 2. It is in the open position. This interval is for absorbing the displacement of the open position when the lens is replaced.

When the release switch SW2 is turned on while the release button is fully pressed, as shown in FIG. 7, the stepping motor 8 is rotated in the reverse direction (rotated in the aperture opening direction) (step S41), and the open position detection switch 12 is turned on. The aperture setting member 4 is driven until it is turned on (step S42).

When the CPU 21 receives the open position detection signal from the open position detection switch 12, the CPU 21 normally rotates the stepping motor 8 (step S43) as shown in FIG. Then, the aperture setting member 4 is driven.

After a little delay from the open position detection signal (step S44), the driving of the sequence lever 13 is started, and as shown in FIG. 9, the diaphragm charge lever 3 is moved against the biasing force of the diaphragm charge spring 10. Drive in the narrowing direction. As a result, the aperture interlocking lever 2 rotates in the aperture direction while being linked with the aperture lever 19 by the urging force of the aperture charge spring 10, and is driven to the limit position set by the aperture setting member 4 to open the aperture opening. Is set. When the diaphragm is set to open, the moving position of the diaphragm setting member 4 is the initial position.

Here, the diaphragm drive means is a reduction mechanism that drives the diaphragm setting member 4 which is a segment gear from the stepping motor 8 via the worm wheel 5 and the hole 6, and the force from the diaphragm setting member 4 side. Is supported at the meshing part of the worm. Therefore, the diaphragm driving spring (not shown) on the photographing lens side can be supported without continuing to energize the stepping motor 8 (FIG. 9).

Exposure is performed in this state (step S 46), and after the exposure, as shown in FIG. 10, the sequence lever 13 is driven in the opposite direction, and the urging force of the iris charge spring 10 causes the iris charge. The lever 3 is charged, and the aperture is returned to the open position via the aperture interlocking lever 2, the aperture lever 19 and the like (step S47).

After the diaphragm is restored, the stepping motor 8 is driven in the diaphragm opening direction, and is rotated in the reverse direction by at least one step less than the forward drive amount to return the diaphragm setting member 4 to the standby position (FIG. 11). The moving position where the diaphragm setting member 4 is set may be on the open side or the narrowing side of the retracted position.

FIG. 5 is a flowchart illustrating the operation of the CPU according to another embodiment. The steps up to step S57 are the same as those in FIG. 4 described above. The stepping motor 8 is normally rotated (step S58), and after the open position detection switch 12 is turned on (step S59), the stepping motor 8 is normally rotated by a set amount (step S60). .. By doing so, it is possible to accurately control the aperture opening regardless of the displacement of the open position when the lens is replaced. With this driving method, the stepping motor 8 is not subjected to an extra load such as the urging force of the diaphragm driving spring, the risk of step-out is reduced, and high-speed driving is possible.

In the present invention, when the aperture lever comes into contact with the aperture interlocking lever, when the taking lens is detached from the camera body or when the taking lens is attached to the camera body, the first photographing is performed other than immediately after the attachment is completed. When the lens comes into contact with the camera body, it is possible that the shooting lens has just been mounted or is being mounted.

In the above case, the push button is operated when the interchangeable lens is detached from the camera body, and the means for detecting the operation of the push button is provided. Should be retracted to the retracted position. When the push button is pressed, the positioning pin on the camera body side is retracted. The positioning pin sets the position where the interchangeable lens is completely attached, and the rotation of the lens is prevented by engaging the positioning pin with the hole on the lens side. Further, it may be possible to detect that all the contacts on the camera side and the lens side that electrically exchange signals between the camera body and the interchangeable lens are separated.

In the case described above, a means for detecting that the positioning pin has been pressed is provided, and the setting member 4 may be retracted to the retracted position by this detection signal. It should be noted that pressing the positioning pin means that the interchangeable lens has come into contact with the camera body for mounting.

In the case described above, there are a plurality of contacts (including a normal ground), and a means for detecting which contact on the camera body side and which contact on the interchangeable lens side is in contact is provided. The setting member 4 may be retracted to the retracted position by a signal. Here, in order to detect whether or not it is immediately before the completion of mounting, for example, it is sufficient to detect that the contact of the contact is shifted by one from the contact at the time of completion.

Although the single-lens reflex camera has been described as an example, the present invention can be applied to a lens shutter type camera.

[0036]

[Effect of the device]

 As described in detail above, according to the first aspect of the invention, the aperture control device is configured so that a gap is provided between the setting means and the aperture interlocking lever when the interchangeable lens is completely attached. Even if an interchangeable lens with is attached, there is no risk of damaging the gear train of the deceleration mechanism.

According to the invention of claim 2, during the image pickup operation, the setting means is configured to move to the initial position and then to the moving position. Therefore, the opening limit position peculiar to the interchangeable lens is set as the opening position of the diaphragm aperture. , The setting position can be accurately positioned at the moving position taken at the time of photographing with reference to the open position.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of a diaphragm control device according to the present invention.

FIG. 2 is a control block diagram showing an embodiment of a diaphragm control device according to the present invention.

FIG. 3 is a flowchart illustrating the operation of the CPU of the aperture control device according to the embodiment.

FIG. 4 is a flowchart illustrating the operation of the CPU of the aperture control device according to the embodiment.

FIG. 5 is a flowchart illustrating an operation of a CPU of a diaphragm control device according to another embodiment.

FIG. 6 is an explanatory diagram showing the operation of the mechanical portion of the aperture control device according to the embodiment.

FIG. 7 is an explanatory diagram showing the operation of the mechanical section of the aperture control device according to the embodiment.

FIG. 8 is an explanatory diagram showing the operation of the mechanical portion of the aperture control device according to the embodiment.

FIG. 9 is an explanatory diagram showing the operation of the mechanical portion of the aperture control device according to the embodiment.

FIG. 10 is an explanatory diagram showing the operation of the mechanical section of the aperture control device according to the embodiment.

FIG. 11 is an explanatory diagram showing the operation of the mechanical section of the aperture control device according to the embodiment.

FIG. 12 is a diagram showing a detection unit of the diaphragm control device according to the embodiment.

[Explanation of symbols]

 1 Frame plate 2 Aperture interlocking lever 3 Aperture charge lever 4 Aperture setting member 5 Worm wheel 6 Worm 7 Motor gear 8 Stepping motor 9 Axis 10 Aperture charge spring 11 Contact 11A Non-conductive member 11B Conductive member 12 Open position detection switch 13 Sequence lever 14 Restriction Pin 19 Aperture lever 21 CPU 22 Photometric element 23 Photometric circuit 24 Stepping motor drive circuit SW1 Half press switch SW2 Full press switch

Claims (4)

[Scope of utility model registration request] 1. An aperture control device provided in a camera in which an interchangeable lens having an aperture and an aperture lever for opening and closing the aperture is provided in a detachable camera, the position of the aperture lever being engaged with the aperture lever. And an aperture interlocking lever that determines the position of the aperture interlocking lever, and setting means that is engageable with the aperture interlocking lever and sets the position of the aperture interlocking lever. It is movable between a moving position which is taken in one direction from the initial position and is taken at the time of shooting, and the aperture interlocking lever is positioned at the open position by the setting means in the initial position and is moved from the open position. Is set to the setting position by the setting means in the moving position, the aperture lever fully opens the aperture when the aperture interlocking lever is in the open position, and the aperture interlocking lever sets the aperture. In the aperture control device that brings the aperture into a closed state from the fully opened state when in the stationary position, the setting means includes a speed reduction mechanism, and is substantially displaced even when an external force is applied by the speed reduction mechanism from the aperture interlocking lever. It is impossible, and at least immediately after the completion of mounting the interchangeable lens where the diaphragm lever comes into contact with the diaphragm interlocking lever, the diaphragm in the open position is located at the retracted position moved in the one direction from the initial position. An aperture control device having a gap with an interlocking lever, which prevents the external force from being received from the aperture interlocking lever. 2. The setting means has a detection means for detecting that the setting means is in the initial position, and during the photographing operation, the setting means moves from the retracted position to the initial position in a direction opposite to the one direction. The aperture control device according to claim 1, wherein the aperture control device moves in the one direction to the movement position when the output is received from the detection means. 3. The setting means includes a stepping motor, and the control setting position is a position narrowed down from the control opening position by at least one step of the stepping motor. Aperture control device. 4. The aperture control device according to claim 1, wherein the speed reduction mechanism includes a worm and a worm wheel.