JP2838820B2 - Camera drive mechanism - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive mechanism used for a camera aperture control device and the like. 2. Description of the Related Art As an aperture control device for a camera, for example, Japanese Patent Application Laid-Open No. Sho 60-162230 discloses a ratchet wheel which rotates in conjunction with a traveling operation of an aperture drive lever, and a ratchet wheel which can be disengaged from the ratchet wheel. An aperture stop claw, a spring that biases the aperture stop claw toward a position where the aperture stop claw is engaged with the ratchet wheel, and an electromagnet that attracts and holds the aperture stop claw at a position away from the ratchet wheel against the force of the spring. What is provided is disclosed. In such an apparatus, the aperture drive lever is moved in the aperture stop direction in response to the photographing start signal while the aperture stop claw is attracted and held by the electromagnet. Then, when the aperture drive lever has traveled a desired amount, the electromagnet is demagnetized and the aperture stop claw is driven by the spring force to a position where it engages with the ratchet wheel, thereby stopping the aperture drive lever. In the above-described apparatus, after the photographing is completed, the aperture stop claw is returned from the engagement position with the ratchet wheel to the adsorption position with the electromagnet in preparation for the next photographing, and is securely restrained at that position. There is a need. For this reason, a return member is provided to engage with the stop pawl and return it to the suction position, and after the return stop claw returns to the suction position, urges the return member in the return operation direction of the stop pawl. Conventionally, an overcharge mechanism for pressing an aperture stop claw against an electromagnet has been provided. Also, if the return member remains engaged with the stop stop claw, the stop stop claw is restrained at the attracted position with the electromagnet even if the electromagnet is demagnetized. An elastic member such as a spring is provided, and the return member is retracted from the movement path of the stop stop claw at the start of photographing. For example, Japanese Utility Model Laid-Open Publication No. 61-11139 discloses a mechanism in which a similar mechanism is applied to a shutter blade mechanism. [0004] In the drive mechanism having the return member and the overcharge mechanism described above, the biasing force of the overcharge mechanism, that is, the return member is biased in the direction of the return operation of the stop pawl. Since the spring for applying the force and the elastic member for urging the return member in the direction away from the stop pawl are separately provided, the number of parts is large and the assembly is troublesome. An object of the present invention is to reduce the number of components of a drive mechanism using an electromagnet. FIG. 1 shows an embodiment of the present invention. A driving mechanism according to the present invention comprises an electromagnet 32 having an attraction force and an attraction position at which the electromagnet 32 is attracted. And a drive member 31 that can be displaced to a separation position that separates from the electromagnet, and a drive member 31 that is displaceably provided at an initial position (lower side) and an operation position (upper side) and that is displaced from the operation position to the initial position. A return member 34 for displacing the return member 34 to the suction position, an elastic member 8 for applying a driving force for displacing the return member 34 from the initial position to the operation position, and a direction from the operation position to the initial position for the return member 34 displaced to the initial position And an overcharge member 8a for providing the urging force, and the overcharge member 8a is provided integrally with the elastic member 8 to achieve the above-described object. Since the overcharge member 8a is provided integrally with the elastic member 8, there is no need to separately provide an overcharge spring or the like. In the means and means for solving the above problems which explain the constitution of the present invention, the drawings of the embodiments are used to make the present invention easy to understand. It is not limited to the example. An embodiment of the present invention will be described with reference to FIG. The aperture control lever 1 is rotatably supported with respect to the axis X1, is provided with a right turning force by a spring 2, and protrudes from a mirror driving lever 3 which is rotatably supported about the axis X1.
And stopped. Mirror drive lever 3 also spring 4
, A notch 5a of the start lever 5 rotatably supported on the axis X2 is engaged with the pin 3b and stopped. The mirror drive lever 3 can be engaged with a pin 6 implanted in a mirror (not shown), and when the pin 6 is pushed upward, the mirror is driven up. A mirror down lever 7 is rotatably supported on an axis X3, and a spring 8 is mounted on the axis X3. One end of the spring 8 is limited to a fixed pin 9, and the other end is bent into a U-shape to hold the pin 7 a of the mirror down lever 7 so that the mirror down lever 7 is provided with a left turning force. A slot 7b formed in the mirror down lever 7 has a magnet reset lever 3 to be described later.
A pin 34a projecting from the pin 4 is loosely fitted, and the U-shaped end 8a of the spring 8 presses the pin 34a downward. And
The lower arm 7c of the mirror down lever 7 can be brought into contact with the pin 3c of the mirror drive lever 3, and the upper arm 7d is in contact with the charge lever 10. An aperture drive lever 11 is rotatably supported about an axis X1, and one end 11a thereof is in contact with an aperture lever 12 which is interlocked with the aperture of the lens. Further, a pin 11b implanted in the aperture control lever 11 extends below the aperture control lever 1, and a spring 13 is stretched between the pin 11b and the pin 1a implanted in the lever 1, and the pin 11b And lever 1 abut each other to generate an internal force. Further, a pin 11c is protrudingly provided at a position where the pin 11c can be brought into contact with the manual aperture lever 14. The sector gear 21 is also supported rotatably with respect to the axis X1. The planting pin 21a of the gear 21 extends below the aperture driving lever 11, a spring 15 is stretched between the pin 21b and the pin 11b, and an internal force is generated between both pins.
The sector gear 21 is a small gear portion 2 of the first speed increasing gear 22.
2a. Large gear portion 22 of first speed increasing gear 22
b meshes with the small gear portion 23a of the second speed increasing gear 23. The large gear portion 23 b of the second speed increasing gear 23 meshes with the gear 24. Pin 23c implanted in second speed increasing gear 23
, A spring 25 is attached, one end of which is limited to a fixed pin 26, and the other end is engaged with a pin 23 d implanted in the gear 23, and the spring 25 exerts a left turning force on the second speed increasing gear 23. Is given. A ratchet wheel 28 and a perforated plate 29 are integrated with the gear 24 via a shaft 27. The perforated plate 29 is provided with a large number of small holes 29a, and the small holes 29a are detected by a photo interrupter 30 provided so as to sandwich the perforated plate 29, and the number of detected small holes is counted. , The rotation angle of the perforated plate 29 is detected. The stop stop claw 31 is rotatably supported with respect to the axis X4. A claw portion 31a is provided at one end so as to engage with the ratchet wheel 28, and the other end is attracted to the stop stop magnet 32. Armature 31b is provided,
The left turning force is given by the spring 33. The stop stop magnet 32 is a combination type magnet, and cuts off the attraction force with the armature 31b when a voltage is applied. As described above, the magnet reset lever 34 is provided with the pin 34a at one end thereof.
4 a is pressed by a U-shaped end 8 a of a spring 8 below a long hole 7 b formed in the mirror down lever 7. Further, the fixing pin 35 is loosely fitted in the elongated hole 34b, and the vertical movement of the reset lever 34 is guided. Further, the reset lever 34 has a bent portion 34c that comes into contact with the stop pawl 31. Next, these operations will be described. In response to the release operation, for example, when the start lever 5 is turned clockwise by a well-known electromagnetic mechanism and the engagement between the notch 5a and the pin 3b is released, the mirror driving lever 3 applies the right turning force of the spring 4 Starts the right-handed rotation while pushing up the mirror pin 6, that is, performing mirror up. As a result, the aperture control lever 1 stopped by the pin 3a is rotated clockwise by the right turning force of the spring 3. As a result, the aperture drive lever 11 and the sector gear 21 also rotate. Aperture drive lever 1
The aperture lever 12 follows the clockwise rotation of 1 and the aperture is stopped down. On the other hand, when the sector gear 21 rotates, the gear 24, the shaft 2 through the first and second speed-up gears 22 and 23.
7. The ratchet wheel 28 and the perforated plate 29 rotate integrally. At this time, the spring force of the spring 25 opposes the spring force of the spring 3 which is the driving force of the sector gear 21, so that the sector gear 2
Each gear rotates while the backlash from the first to the second speed increasing gear 23 is moved in one direction. Also, sector gear 2
The first drive amount is expanded by the first and second speed increasing gears 22 and 23 and is taken out from the shaft 27 and the like. Pulses from the photo interrupter 30 are counted by a counter of a control circuit (not shown), and when the count reaches a desired aperture value, a voltage is applied to the magnet 32 from the control circuit to release the armature 31b. As a result, the right stop force of the spring 33 causes the stop stop claw 31 to turn left, and the claw portion 31a engages with the ratchet wheel 28 to stop this rotation. Therefore, all the systems from the aperture control lever 1 to the ratchet wheel 28 stop, and the aperture value of the lens is set. The mirror driving lever 3 completes the mirror up operation irrespective of such a stop, and the mirror is retracted from the photographing optical path. Next, a shutter (not shown) is operated by a well-known device to perform a shooting operation, and subsequently, a reset operation of each unit is performed. Next, the reset operation will be described.
When the charge lever 10 is turned clockwise (in the direction of the arrow in FIG. 1) by a known mechanism such as a motor drive, the mirror down lever 7
The upper arm 7d is pushed, and the lever 7 turns clockwise around the axis X3. The lever lower arm 7c is connected to the pin 3 of the mirror driving lever 3.
c is pressed against the spring 4, and the lever 3 is turned counterclockwise around the axis X1. For this reason, the mirror drive lever end 3d pushing up the mirror pin 6 escapes, and the mirror (not shown) integrated with the mirror pin 6 starts down drive so as to return to the position before the release. This mirror down drive is performed to a position where the pin 3b can be engaged with the notch 5a of the start lever 5. At this time, the pin 3a contacts one end 1b of the aperture control lever 1 stopped at a position corresponding to a certain aperture value,
The aperture control lever 1 turns left around the axis X1. Here, the coupling spring 13 between the aperture control lever 1 and the aperture drive lever 11 is set to have a greater coupling torque than the coupling spring 15 between the aperture drive lever 11 and the sector gear 21. For this reason, the magnet 3
At the time when the resetting operation of the armature 34c for the armature 2 has not been completed, that is, the ratchet wheel 28
Before being released from the gear, the aperture control lever 1 and the aperture drive lever 11 perform a return operation while charging the spring 15 with the gear train from the sector gear 21 to the ratchet wheel 28 remaining. By this return operation, the aperture lever 12 of the lens is pushed upward and the aperture is opened. On the other hand, as the mirror down lever 7 rotates clockwise, the pin 34a inserted in the elongated hole 7b
The reset lever 34 starts to move downward because it is pushed down by the character-shaped end 8a. Here, the U-shaped end 8a of the spring 8
Presses the pin 34a below the elongated hole 7b by the spring 3
Since the left turning force of the stop stop claw 31 given by 3 is set to be greater than the force pressing the reset lever 34 upward, the mirror down lever 7 causes the armature 31b to stop stopping through the reset lever 34. The stop stop claw 31 turns clockwise until it is attracted to the magnet 32. After the armature 31b is attracted, the mirror down lever 7 continues clockwise. At this time, reset lever 3
4 can no longer move downward, so that the mirror down lever 7 turns clockwise while bending the U-shaped end 8a of the spring 8,
As a result, the aperture stop claw 31 is overcharged so that the armature 31b is securely attracted to the magnet 32. As described above, in this embodiment, the aperture stop pawl is provided by the spring 8 which provides the driving force for the returning operation of the mirror down lever 7 (turning left around the axis X3) and the retreating operation of the reset lever 34 upward. Since an overcharging force is provided at the time of resetting of 31, the other overcharging mechanism becomes unnecessary, which is effective in reducing the number of parts. Note that, as described above, the armature 31b
When the engagement between the pawl 31a and the ratchet wheel 28 is released in the process in which the ratchet wheel 28 is attracted to the magnet 32, the ratchet wheel 2
The speed increasing gear system from the gear 8 to the sector gear 21 includes springs 15 and 2.
It returns to the initial position before the start of release by the force of 5. At this time, since the spring force of the spring 25 eliminates play (backlash) of each gear, the initial position of each member is stabilized. In the above embodiment, the stop stop magnet 3
2 is an electromagnet, a stop stop claw 31 is a drive member, a reset lever 34 is a return member, a spring 8 is an elastic member, and a spring 8
U-shaped end portion 8a constitutes an overcharge member. The present invention can be applied to a driving mechanism of an autofocus lens and a shutter blade in a so-called autofocus camera. As described above, according to the present invention,
Since it is not necessary to separately provide an overcharge spring or the like, the number of components and the number of assembling steps of the drive mechanism using the electromagnet can be reduced.

[Brief description of the drawings] FIG. 1 is a perspective view showing one embodiment of the present invention. [Explanation of symbols] 1 Aperture control lever 3 Mirror drive lever 5 Start lever 6 Mirror pin 7 Mirror down lever 8 Spring 8a U-shaped end of spring 11 Aperture drive lever 12 Aperture lever 28 ratchet car 31 Aperture stop claw 32 Stop Stop Magnet 34 Reset lever

Claims (1)

(57) [Claims] An electromagnet having an attraction force; a driving member displaceable to an attraction position adsorbing to the electromagnet and a detached position away from the electromagnet; and a drive member displaceably provided at an initial position and an operation position; A return member that displaces the drive member from the separation position to the suction position by a displacement to an elastic member that applies a driving force to displace the return member from the initial position to the operating position; An overcharge member for applying a biasing force to the return member in a direction from the operation position to the initial position, wherein the overcharge member is provided integrally with the elastic member. Drive mechanism.