JPH0559434U - Shutter drive mechanism that doubles as a lens drive mechanism - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the motor load in a mechanism that sequentially drives a lens mechanism and a shutter mechanism using a single motor as a drive source. [Structure] When the pinion 21 rotates counterclockwise, the drive ring 24 also rotates counterclockwise, and in the process, the lens drive ring 25 is also rotated counterclockwise, and the lens barrel 26 is extended to the target position. When the pinion 21 turns right after that, the lens drive ring 25 also turns right, but since the lens barrel extension cam is the stepped cam 25a, the lens drive ring 25 stops at the in-focus position without the ratchet mechanism. The open / close lever 28 is opened / closed in accordance with the clockwise rotation of the drive ring 24, and the lens drive ring 25 is rotated in the process of the drive ring 24 passing the initial position and further rotated clockwise.
Returns to the initial position. Therefore, the return spring of the lens drive ring 25 is not required and the ratchet mechanism is not required, so that the motor load can be reduced.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a shutter drive mechanism that also serves as a lens drive mechanism, and in particular, is designed to reduce the load on the step motor based on a mechanism that drives the lens mechanism and the shutter mechanism using a single step motor as a drive source. The present invention relates to a shutter drive mechanism that also serves as a lens drive mechanism.

[0002]

[Prior Art]

 Conventionally, a mechanism is known in which a single step motor is used as a drive source to drive a lens mechanism and a shutter mechanism. In this type of mechanism, the lens drive mechanism is generally aimed by rotating the step motor. Then, the lens drive mechanism is positioned by the ratchet mechanism, etc., the step motor is reversed, the shutter mechanism is released, and then the shutter is returned to the initial position.

FIG. 8 shows a preferred example of the conventional mechanism of the related art. The structure will be described together with its operation. When the output pinion 2 of the step motor 1 rotates counterclockwise, the rotation of the output pinion 2 is divided into a two-stage gear 3 and a ring. It is transmitted to the drive member 4 through a rack 4a formed on the outer edge of the drive member 4, and the drive member 4 is rotated counterclockwise. In the left-handed rotation process of the drive member 4, the pin 4b implanted in the drive member 4 engages the engagement step portion 5a of the ring-shaped lens drive member 5 to rotate the lens drive member 5 leftward. Three convex cams 5b are formed at 120 ° intervals on the object side surface of the lens driving member 5, and inclined cam edges supported by the convex cams 5b are formed at 120 ° intervals on the lens barrel (not shown). Therefore, when the lens drive member 5 rotates counterclockwise, the lens barrel (not shown) is extended.

When the lens driving member 5 is rotated counterclockwise to the intended focus position, the output pinion 2 is inverted to rotate the driving member 4 clockwise. At this time, the ratchet gear 5c of the lens driving member 5 is pivotally supported on the shaft 7. The ratchet lever 6 is engaged with the click 6a of the ratchet lever 6 and stays at the in-focus position. Reference numeral 8 denotes an opening / closing lever pivotally supported by a shaft 9 and given a right turning force by a spring 10. A pin 8a formed on the back surface of the opening / closing lever 8 engages with a shutter blade (not shown). When the open / close lever 8 is turned to the right, the shutter blade (not shown) is opened.

As described above, the tilting cam 8b formed on the opening / closing lever 8 is attached to the outer edge portion of the driving member 4 in the right turning process in which the driving member 4 returns to the initial position after turning the lens driving member 5 counterclockwise. When it drops from the formed cam edge 4c to the concave cam 4d, the opening / closing lever 8 is rotated clockwise by the spring 9 to open the shutter blade (not shown), and the driving member 4 is further rotated rightward so that the inclined cam 8b is concave. When the cam 4d rides on the cam edge 4e, the opening / closing lever 8 turns counterclockwise against the spring 9 to close the shutter blade (not shown).

Then, immediately before the driving member 4 further rotates rightward and returns to the initial position, the projection 4f formed on the driving member 4 flips up the cam 6b of the ratchet lever 6, and the ratchet lever 6 causes the spring 11 to move. The ratchet gear 5c of the lens driving member 5 is opened by rotating counterclockwise against the above, and the lens driving member 5 is rotated clockwise by the spring 12 to return to the initial position, and one photographing operation is completed.

[0007]

[Problems to be solved by the device]

 As is apparent from the above description, in the case of the conventional mechanism of this type, in addition to the inertial force of various mechanism members when the step motor 1 rotates normally, the spring 11 for operating the ratchet lever 6 and the lens Since the spring 12 for returning the driving member 5 to the initial position is also added as a load, the load of the step motor 1 becomes extremely large. Therefore, it becomes necessary to increase the motor output and the motor supply voltage increases. This increase in the motor supply voltage causes an increase in the battery check voltage of the entire camera, which in turn reduces the number of shots that can be taken. In addition, since the motor output is improved, the motor itself becomes large, and the shutter mechanism becomes large.

[0008]

The present invention has been made in view of such problems, and a spring 12 and a ratchet lever for returning the lens driving member 5 in the above-described conventional mechanism to the initial position. An object of the present invention is to provide a shutter drive mechanism that doubles as a lens drive mechanism, by which a motor load can be reduced by providing a new mechanism capable of removing the spring 11 for operating 6.

In summary, the lens shutter driving mechanism of the present invention, which also serves as the lens driving mechanism, is similar to the above-mentioned conventional mechanism described above, in that the driving member connected to the step motor advances in the process of moving forward. Drive the photographic lens system on the premise of a mechanism that opens and closes the sector while the drive member moves in the opposite direction toward the initial position of the drive member after advancing to the target in-focus position. The lens drive cam for this purpose is composed of at least a stepped cam having a number of steps corresponding to the set number of steps of the taking lens, and the lens drive member has a drive member that moves in the opposite direction from the initial position of the drive member. By forming the second engaging portion to be engaged with, it is possible to remove the spring for returning the initial position of the lens driving member and the ratchet mechanism, The above object is achieved.

[0010]

[Action]

 That is, according to the present invention, the lens driving member is engaged with the second engaging portion as the sector opening / closing member is operated and the driving member is moved in the reverse direction after passing through the initial position. As a result, the spring is returned to the initial position, and the spring for returning the lens drive member to the initial position can be removed. Then, the spring for returning the initial position of the lens driving member is removed, and the lens driving cam for driving the taking lens system is configured by a stepped cam having at least a step number corresponding to the set step number of the taking lens. As a result, the lens can be positioned even if the ratchet mechanism is removed. Therefore, the spring for returning the initial position of the lens driving member and the ratchet mechanism are not added to the motor as a load, and the load can be reduced.

[0011]

Embodiments Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a shutter driving mechanism that also serves as a lens driving mechanism according to one embodiment of the present invention, and FIG. 2 is a perspective exploded view showing a part of the shutter driving mechanism. The output pinion 21 of the step motor 20 meshes with a rack 24a formed on the drive ring 24 via a two-stage gear consisting of a large-diameter gear 22 and a small-diameter gear 23, and the rotation of the output pinion 21 is transmitted through the transmission train. Is transmitted to the drive ring 24 through the drive ring 24, and the drive ring 24 turns in the same direction as the output pinion 21 about the center of the exposure aperture.

Next, like the drive ring 24, a lens drive ring 25 is supported so as to be rotatable around the center of the aperture for exposure. The lens drive ring 25 has 120 ° on the side surface of the object. Stepped cams 25a, 25b, and 25c are formed at the same intervals as the set number of steps of the taking lens. Reference numeral 26 is a lens barrel in which a photographing lens is inserted, and cam followers 26a, 26b and 26c formed at 120 ° intervals on the outer side of the lens barrel 26 are respectively attached to stepped cams 25a, 25b and 25c. The lens barrel 26 is urged toward the lens drive ring 25 by the spring 27. Therefore, when the lens driving ring 25 rotates counterclockwise, the lens barrel 26 is gradually extended.

On the back surface of the lens drive ring 25, an engagement pin 25d located on the left-handed path of the engagement end surface 24b formed at the outer edge of the drive ring 24 is planted, and is engaged with the engagement end surface 24b. In the process in which the engagement pin 25d forms the first engagement portion and the drive ring 24 rotates counterclockwise from the initial position, the lens drive ring 25 moves from the time when the engagement end surface 24b engages the engagement pin 25d. Follow to turn left.

Furthermore, on the back surface of the lens drive ring 25, an engagement pin 25e located on the right-handed path of the engagement end surface 24c formed at the outer edge of the drive ring 24 is planted. 24c and the engagement pin 25e form a second engagement portion, and in the process of the drive ring 24 turning clockwise from the initial position, the lens drive ring 25 starts from the point when the engagement end surface 24c engages the engagement pin 25e. Rotates right by being driven by the drive ring 24.

Next, reference numeral 28 denotes an opening / closing lever for driving the shutter blades to open and close. The opening / closing lever 28 is pivotally supported by a shaft 29 so as to be swingable, and a right turning characteristic is given by a spring 30. In the initial state, rightward rotation is restricted at a position where the cam follower 28a formed on the opening / closing lever 28 contacts the cam edge 24d formed on the outer edge of the drive ring 24. As shown in FIG. 3, a shutter blade 33 is swingably supported on a shaft 32 on the back surface of the main plate 31, and a pin 28b planted on the back surface of the opening / closing lever 28 is formed on the shutter blade 33. When the opening / closing lever 28 is rotated clockwise by engaging with the elongated hole 33a, the shutter blade 33 rotates clockwise about the shaft 32 to open the exposure aperture 31a. Although not shown in the drawing, a shutter blade (not shown) having a symmetrical shape with the shutter blade 33 is pivotally supported on the shaft 34 of the main plate 31, and the shutter blade (not shown) also operates in common with the shutter blade 33. do.

The operation of the cam edges 24e, 24f, 24g formed on the drive ring 24 and the cam edge 25f formed on the lens driving ring 25 will become apparent from the later description of the operation.

Next, the operation of this embodiment will be described with reference to the above matters and FIGS. 4 to 7. First, in the initial state, the mechanism is in the state shown in FIG. 1. From this state, when the forward rotation pulse is supplied to the step motor 20 to rotate the output pinion 21 counterclockwise, the rotation is large gear 22-small gear 23- It is transmitted to the drive ring 24 via the transmission train of the rack 24a, and the drive ring 24 is rotated counterclockwise. The cam edge 24g and the cam edge 24f formed on the drive ring 24 in the counterclockwise process of the drive ring 24 pass through the position of the cam follower 28a of the open / close lever 28, and the open / close lever 28 is slightly rotated right by the spring 30. The cam follower 28a does not come into contact with the cam edge 25f of the lens drive ring 25 to open the shutter blade 33.

In this way, from the time when the engaging end surface 24 b formed on the drive ring 24 engages the engaging pin 25 d planted on the lens drive ring 25 during the process of the drive ring 24 turning counterclockwise, The drive ring 25 follows the drive ring 24 and rotates counterclockwise. Therefore, in the lens barrel 26, the cam followers 26a, 26b, 26c are driven by the corresponding stepped cams 25a, 25b, 25c, and are extended toward the subject against the spring 27.

FIG. 4 shows a state in which the lens drive ring 25 is turned counterclockwise to the maximum extended position in this way, and at this time, the open / close lever 28 is in the shutter closed state because the cam follower 28a contacts the cam edge 24e of the drive ring 24. Is maintained.

As described above, when the lens drive ring 25 is rotated counterclockwise to the intended focus position and then the reverse rotation pulse is supplied to the step motor 20 to rotate the output pinion 21 clockwise, the output pinion 21 is already rotated. It is transmitted to the drive ring 24 via the transmission train described above, and the drive ring 24 also rotates to the right. In this embodiment, the cam for moving out the lens barrel 26 is composed of a stepped cam corresponding to the set number of steps of the photographing lens, and the flat parts of the stepped cams 25a, 25b, 25c respectively correspond to the cam followers 26a. Since 26b and 26c are supported, no external force is generated to rotate the lens drive ring 25, and the lens drive ring 25 stops at the target focus position.

When the drive ring 24 is turned clockwise in this way, the cam follower 28 a of the opening / closing lever 28 falls from the cam edge 24 e of the drive ring 24 to the cam edge 24 f, and the opening / closing lever 28 is turned clockwise by the spring 30. FIG. 5 shows the state at this time. When the opening / closing lever 28 is turned clockwise, the shutter blade 33 is turned clockwise about the shaft 32 while being engaged with the pin 28b at the tip thereof, and the exposure aperture 31a is opened. The step motor is stopped for a time corresponding to the desired exposure time.

When the desired exposure time elapses, the output pinion 21 of the step motor 20 again starts clockwise rotation, and the opening / closing lever 28 causes the cam follower 28a to move from the cam edge 24g of the drive ring 24 to the cam edge 24d. Since it rotates counterclockwise around 29, the shutter blade 33 rotates counterclockwise around the shaft 32 to close the exposure aperture 31a.

FIG. 6 shows a state in which the opening / closing lever 28 is rotated counterclockwise in this way. After the exposure operation is completed, the stepping motor 20 is continuously supplied with the reversal pulse, and the output pinion 21 is further rotated clockwise. The drive ring 24 also rotates rightward beyond the initial position. During the clockwise rotation of the drive ring 24, the lens drive ring 25 moves from the time when the engagement end surface 24c formed on the drive ring 24 engages the engagement pin 25e implanted in the lens drive ring 25. Follow and turn right. Therefore, the lens barrel 26 is retracted to the initial position by the urging force of the spring 27 while the cam followers 26a, 26b, 26c descend the corresponding stepped cams 25a, 25b, 25c. FIG. 7 shows a state in which the lens driving ring 25 thus returned to the initial position. After the lens driving ring 25 returns to the initial position, a forward rotation pulse is applied to the step motor 20 to rotate the output pinion 21 counterclockwise. One shooting operation is completed by returning the drive ring 24 to the initial position.

In the above description, the stepped cam is explained on the assumption that the inclined surface and the flat surface are alternately repeated, but the inclined surface in the feeding direction and the inclined surface in the opposite direction are alternately repeated. Good. Also, in the above, an example was shown in which a stepped cam was formed on the lens drive ring side and a cam follower was formed on the lens barrel side, but a stepped cam may be formed on the lens barrel side. .. In addition, although an example in which the opening / closing lever is directly driven by a cam formed on the drive ring has been shown above, any known mechanism can be used as long as it is a mechanism that operates the opening / closing lever during the return process of the drive ring. Needless to say, can be adopted. Furthermore, although an example in which the drive ring, the lens drive ring, or the aperture is pivotally moved has been shown above, it goes without saying that the present invention can be applied to the case of linear operation.

[0025]

[Effect of the device]

 As described above, according to the present invention, the ratchet mechanism for positioning the lens driving member at the in-focus position, the spring for initially returning the lens driving member, etc. are mechanically unnecessary. There is no need to rotate while charging the ratchet mechanism or the spring for initial return. Therefore, the load applied to the motor is greatly reduced, the motor can be downsized, and the drive voltage of the motor can be reduced, so that the required battery power can be reduced. The pressure is low and the number of pictures that can be taken increases.

[Brief description of drawings]

FIG. 1 is a plan view of an initial state of a shutter drive mechanism that also serves as a lens drive mechanism according to an embodiment of the present invention.

FIG. 2 is a perspective exploded view of the above embodiment.

FIG. 3 is a plan view of a blade peripheral mechanism according to the present invention.

FIG. 4 is a plan view of the lens maximum extension state of the embodiment shown in FIG.

5 is a plan view of the shutter opening state of the embodiment shown in FIG.

FIG. 6 is a plan view of the embodiment shown in FIG. 1 at the end of closing the shutter.

FIG. 7 is a plan view showing a state where the lens driving ring of the embodiment shown in FIG. 1 is initially returned.

FIG. 8 is a plan view of a conventional seed mechanism.

[Explanation of symbols]

 1 1st lens 2 2nd lens 3 3rd lens 4 4th lens 5 5th lens 20 Step motor 24 Drive ring 24b Engagement end face 24c Engagement end face 25 Lens drive ring 25a Stepped cam 25b Stepped cam 25c Stepped cam 25d Engagement pin 25e Engagement pin 28 Opening / closing lever 32 Shutter blade

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G03B 13/34 9/10 D 8807-2K

Claims (1)

[Scope of utility model registration request] 1. A forward / reverse rotatable step motor, a drive member connected to the step motor for traveling in both forward and reverse directions, a lens drive cam for driving a photographing lens, and the drive member from the initial position to the forward position. The lens driving member formed with a first engaging portion that is engaged with the driving member only when traveling in the direction, and the driving member is moved forward until the lens driving member reaches a target focusing position. In a shutter drive mechanism that also serves as a lens drive mechanism, the shutter drive mechanism includes a sector opening / closing member that opens / closes a sector in the process in which the drive member travels in the opposite direction toward the initial position after traveling in the direction. It is composed of a stepped cam having a step number corresponding to the set step number of the photographing lens, and the lens driving member is provided only when the driving member travels in the reverse direction from the initial position. A second engaging portion to be engaged with the drive member is formed, and the drive member is moved in the reverse direction after the operation of the sector opening / closing member until the lens drive member reaches the initial position of the lens drive member. A shutter drive mechanism that doubles as a lens drive mechanism, characterized by being driven.