JPH103108A - Curtain speed adjusting mechanism for camera shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce camera-shake by switching the standstill position of a supporting member to plural places with a switching means, simultaneously with the operation of selecting the shutter speed, that is, the exposure time. SOLUTION: In this curtain speed adjusting mechanism, in the shutter speed at a shortest shutter opening time, a control circuit, to which a selecting signal for the shutter speed by a shutter speed dial is inputted, actuates a step motor 13 by a specific rotational amount. For instance, when the step motor 13 is rotated once with respect to a reference position, a gear train is rotated and the supporting member 5 is rotated by a specific amount, in a direction where the energizing force of an opening lever spring is increased, to increased the speed of a curtain up to a desired value. In the shutter speed of a long shutter opening time, when the shutter speed dial is set in the reference position, the control circuit to which the selecting signal by the shutter speed dial is inputted actuated the step motor 13, to reversely rotate it once and return it to the reference position, so that the supporting member 5 is rotated by a specific amount in an opposite direction where the energizing force of the opening lever spring is reduced, to decrease the speed of the curtain up to the desired value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shutter speed adjusting mechanism for a camera shutter.

[0002]

2. Description of the Related Art A conventional shutter speed adjusting mechanism for a camera shutter is disclosed, for example, in Japanese Utility Model Publication No.
There is a publication described in each gazette such as -39374, which is shown in FIG. 5 when illustrated. In the figure, reference numeral 101 denotes a base plate, and 101a denotes an exposure opening formed in the base plate 101. An opening lever 102 and a closing lever 106 as sector drive levers are provided on the base plate 101.
Are rotatably provided around the shafts 101d and 101e, respectively. A sector drive pin 102b is provided at the tip of the release lever 102.
02b is a sector drive groove 101b formed in the base plate 101.
And is connected to an open sector (not shown).
A sector drive pin 106 is provided at the tip of the closing lever 106.
b, and the sector driving pin 106 b is
No. 01 is connected to a closed sector (not shown) through a sector drive groove 101c.

A ratchet wheel 105 is provided around the axis 101d of the opening lever 102 so as not to rotate reversibly. An opening lever spring 104 is interposed between the ratchet wheel 105 and the opening lever 102. That is, one end of the release lever spring 104 is locked to the spring boss 102d of the release lever 102, and the other end of the release lever spring 104 is locked to the spring boss 105a of the ratchet wheel 105. An opening electromagnet 103 is arranged near the opening lever 102 of the base plate 101.
The iron core 103a of the opening lever 102 is an iron piece 1
The release lever 102 is attracted by the release lever 102c to restrict the rotation of the release lever 102. When the power is not supplied, the release lever 102 is released and the release lever 102 is urged by the release lever spring 104 to rotate to perform the sector release operation. I have.

The closing lever 106 is provided with a ratchet wheel 109, a closing lever spring 108, spring bosses 106d and 109a, a closing electromagnet 107, an iron core 107a, and an iron piece 106c having the same functions.
The rotation of the motor 6 is restricted or released to perform the sector closing operation.

A claw holder 110 is fixed to the base plate 101. The claw holder 110 has a ratchet claw 110a engaging with a ratchet wheel 105 and a ratchet claw 110b engaging with a ratchet wheel 109. The ratchet pawls 110a and 110b allow the ratchet wheels 105 and 109 to rotate in the counterclockwise direction in the figure, but function to restrict the reverse clockwise rotation.

In such a conventional shutter speed adjusting mechanism for a camera shutter, the driving force of the opening / closing sector is determined via the opening / closing levers 102, 106 by the biasing force of the opening / closing lever springs 104, 108, and the driving force of the opening / closing sector is small. In some cases, the ratchet wheels 105 and 109 are rotated in a counterclockwise direction during assembly or repair, so that the ratchet pawl 11 is rotated.
By changing the position of engagement with the opening and closing levers 0a and 110b to increase the urging force of the opening and closing lever springs 104 and 108, the time during which the opening and closing sector travels through the exposure opening 101a, that is, the curtain speed is adjusted.

[0007]

With the recent increase in shutter speed (shortening of the exposure time), the width of the slit formed by the sector has become narrower, and it has become difficult to maintain the accuracy thereof. Therefore, in order to make the width of the slit equal to the conventional width, the curtain speed is increased to cope with the problem. For example, for the shortest exposure time of 1/2000 seconds, the length is 24 mm.
The sector travels through the exposure opening of 7.5 ms in 7.5 ms, while the sector travels through the same length of exposure opening in 2.8 ms for the shortest exposure time of 1/8000 second. By the way, in the above-mentioned conventional example, the curtain speed is the same whether the exposure time is short or long.
Even at 125 seconds, the sector runs in the same time 2.8 ms. For this reason, it is not so on the high speed second side,
There is a problem that the whole camera vibrates due to the recoil at the start of the sector and the shock at the stop from the full opening second (strobe synchronization time) to the low-speed second side, so-called camera shake is likely to occur (JCII Report N).
o. 482-12).

[0008]

According to the mechanism for adjusting the shutter speed of the camera shutter having such a structure, the switching means switches the rest position of the support member to a plurality of positions simultaneously with the selection operation of the shutter speed, that is, the exposure time. As a result, the biasing force of the sector drive spring whose locking end is supported by the support member can be changed, so that the rotation speed of the sector drive lever biased by the sector drive spring, that is, the opening / closing operation of the shutter opening Can be changed according to the shutter speed. For this reason, the curtain speed on the low-speed side can be made slower than the curtain speed on the high-speed side, and camera shake at the start or stop of a sector can be reduced.

[0009]

In order to solve the above-mentioned problems, a shutter speed adjusting mechanism for a camera shutter according to the present invention includes a sector drive lever for driving a sector to open and close a shutter opening; A sector drive spring for urging in the opening and closing operation direction of the sector drive, a support member for supporting a locking end of the sector drive spring, and a stop of the support member for changing the urging force of the sector drive spring in accordance with a shutter speed. Switching means for moving the position to an arbitrary position. Further, before winding the film, the switching means is operated in a direction to weaken the urging force of the sector drive spring, and after winding the film, the urging force of the sector drive spring corresponds to a shutter speed, and is lower than the weak urging force. The switching means may be operated at an arbitrary position where a strong urging force is applied.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a view showing a first embodiment of a curtain speed adjusting mechanism of a camera shutter according to the present invention. In the figure, reference numeral 5 denotes a support member constituted by a worm gear. The support member 5 is arranged in a positional relationship corresponding to the ratchet wheel 105 in the above-described conventional example, and also has an open lever spring (104 in FIG. 5) between the support member 5 and the open lever (102 in FIG. 5) as in the conventional example. At the same time, one end (locking end) of the open lever spring is locked and supported by a spring hook boss 5a. A worm 10 meshes with the worm gear at the peripheral portion of the support member 5, and the worm 10 further includes spur gears 11 and 1.
The rotation is driven by the step motor 13 through the second motor 2. And this step motor 13
The operation is controlled by a control circuit (control means) shown in FIG.

FIG. 4 is a block diagram showing a control circuit. The control circuit has a well-known photometric circuit section 51, a shutter speed setting section 52, and a film advance detecting section 53. These information are introduced into a control circuit section 54. The result is output to the motor drive unit 55 to drive the step motor 13. Therefore, the rotation amount of the step motor 13 is determined according to the shutter speed setting position of the second dial (not shown). That is, when the film winding detection unit 53 does not detect film winding, the control circuit unit 54 sends a signal for reversing the step motor 13 to the motor driving unit 55 to attach a driving lever spring (opening and closing lever spring). After the camera is turned by a predetermined amount in the direction to decrease the power, the winding of the camera is started.

When the film winding detecting unit 53 detects the film winding, if the shutter speed setting unit 52 outputs a signal for setting the time longer than 1/125 second, the control circuit unit 54 No signal is output to the drive unit 55, and the step motor 13 does not rotate. When the shutter speed setting unit 52 outputs a signal at a time shorter than 1/125 second, a normal rotation signal is output from the control circuit unit 54 to the motor driving unit 55, and the step motor 13 is rotated to drive the driving lever spring ( The lever is rotated by a predetermined amount in a direction to increase the urging force of the opening and closing lever springs) and stopped.

When the shutter speed setting unit 52 is at the auto position, the shutter speed is automatically set by a signal from the photometry circuit unit 51, and when a signal at a time longer than 1/125 second is set, From the control circuit unit 54 to the motor drive unit 55
Does not output a signal, and the motor 13 does not rotate. When a signal at a time when the shutter speed is shorter than 1/125 second is set, a normal rotation signal is output from the control circuit unit 54 to the motor drive unit 55, and the step motor 13 is rotated to drive the drive lever spring (open, closed). The lever is rotated by a predetermined amount in the direction of increasing the urging force of the lever spring and stopped.

In such a shutter speed adjusting mechanism for a camera shutter, for example, the shutter opening time is the shortest.
When the shutter speed is / 8000 seconds, the control circuit, which has input the shutter speed selection signal by the second dial, activates the step motor 13 by a predetermined amount of rotation, for example, by rotating the step motor 13 once with respect to the reference position. By rotating the gear train, the support member 5 is rotated by a predetermined amount in a direction to increase the urging force of the opening lever spring, and the curtain speed can be increased to a desired value.

Further, for example, the shutter opening time is 1/12
When the shutter speed is longer than 5 seconds, the second dial is set to the reference position, and the control circuit, which has received a selection signal from the second dial, activates the step motor 13 and reversely rotates the step motor 13 by one rotation. By returning to, the support member 5 can be rotated by a predetermined amount in the reverse direction to reduce the urging force of the opening lever spring, and the curtain speed can be reduced to a desired value. In this manner, the curtain speed on the low-speed side can be made slower than the curtain speed on the high-speed side, and camera shake at the start or stop of a sector can be reduced.

In the first embodiment, the case where the supporting member 5 is related to the opening lever and the opening lever spring has been described.
06) and closing lever springs (108 in FIG. 5).

FIG. 2 shows a second embodiment of the present invention. In the figure, reference numeral 15 denotes a support member constituted by a spur gear. The support member 15 is arranged in a positional relationship corresponding to the ratchet wheel 105 in the above-described conventional example, and also has an open lever spring (104 in FIG. 5) between the support member 15 and the open lever (102 in FIG. 5) as in the conventional example. At the same time, one end (locking end) of the release lever spring is locked and supported by a spring hook boss 15a. Reference numeral 19 also denotes a support member constituted by a spur gear, and this support member 19 is disposed in a positional relationship corresponding to the ratchet wheel 109 in the above-mentioned conventional example. ), A closing lever spring (108 in FIG. 5) is interposed, and one end (locking end) of the closing lever spring is locked and supported by a spring hook boss 19a. The switching gear 20 is attached to these support members 15 and 19.
Are engaged with each other, and this switching gear 20
1, and the switching gear 20 can be driven by rotating the time dial 21.

In the second embodiment, for example, as shown in FIG.
When the second dial 21 is turned to match the index (の in the figure) to select the second shutter speed, the switching gear 2
0 is driven to rotate clockwise in the drawing, thereby rotating the support members 15 and 19 counterclockwise. When the supporting members 15 and 19 rotate counterclockwise in this manner, the urging force of each lever spring increases, the curtain speed increases to increase the amount of force for driving each sector, and the exposure opening (see FIG. 5). 101a) can run the sector in 2.8 ms.

Next, when the second dial 21 is rotated to match the index in order to select a shutter speed with a shutter release time of 1/4000 second, the switching gear 20 is driven to rotate counterclockwise in the figure. By moving the support member 1
5, 5 are rotated clockwise. When the support members 15 and 19 rotate clockwise in this manner, the urging force of each lever spring decreases, and the curtain speed decreases to reduce the amount of driving force for each sector. You can run the sector.

As described above, at the same time as the shutter speed selecting operation, the switching gear 20 as the switching means is rotated, and the supporting member 1 is rotated.
By switching the resting positions of the spring bosses 15a, 19a, ie, the resting positions of the spring bosses 15a, 19a, the urging force of each lever spring whose locking end is supported by the support members 15, 19 can be changed. The rotation speed of each lever, that is, the curtain speed at the time of opening and closing the shutter opening can be adjusted.

FIG. 3 shows a third embodiment of the present invention. In the figure, reference numeral 25 denotes a support member constituted by a spur gear. The support member 25 is arranged in a positional relationship corresponding to the ratchet wheel 105 in the above-described conventional example, and also has an open lever spring (104 in FIG. 5) between the support member 25 and the open lever (102 in FIG. 5) as in the conventional example. At the same time, one end (locking end) of the release lever spring is locked and supported by a spring hook boss 25a. Reference numeral 29 also denotes a support member constituted by a spur gear, and this support member 29 is disposed in a positional relationship corresponding to the ratchet wheel 109 in the above-described conventional example. ), A closing lever spring (108 in FIG. 5) is interposed, and one end (locking end) of the closing lever spring is locked and supported by a spring hook boss 29a.

A substantially semicircular switching gear 30 is meshed with both of the support members 25 and 29. The switching gear 30 is connected to a time dial (not shown) by a known method. By rotating the switch gear 30, the switching gear 30 is driven, and the arm 30 a of the switching gear 30 is rotated to come into contact with the stopper 31 or 32. In the third embodiment, the second dial has a shutter release time of 1/8000 to 1/2.
In the case where the shutter speed is within the range of 50 seconds, the switching gear 30 is rotated clockwise in FIG. 3 so that the arm 30a comes into contact with the stopper 31 as shown in FIG. 25 and 29 are rotated counterclockwise. When the support members 25 and 29 rotate in the counterclockwise direction in this manner, the urging force of each lever spring increases, the curtain speed increases to increase the amount of force for driving each sector, and the exposure opening is moved for 2.8 ms. Can run the sector.

Next, when the second dial indicates that the shutter release time is 1
In the case where the shutter speed is in the range of / 125 to 1/1 second, the switching member 30 rotates counterclockwise in the drawing so that the arm portion 30a comes into contact with the stopper 32. 25 and 29 are rotated clockwise. When the support members 25 and 29 rotate clockwise in this manner, the urging force of each lever spring is reduced, and the curtain speed is reduced in order to reduce the amount of driving force for each sector. You can run the sector.

As described above, similarly to the second embodiment, the switching gear 30 as switching means is rotated simultaneously with the selection operation of the shutter speed, and the stationary positions of the support members 25, 29, ie, the spring-loaded bosses 25a, 29a are set. By switching, the urging force of the sector drive spring whose locking end is supported by the support members 25 and 29 can be changed. Therefore, the rotation speed of the sector drive lever urged by the sector drive spring, that is, the shutter The curtain speed at the time of opening and closing the opening can be adjusted. In the second and third embodiments, the switching gear is driven by the second dial. However, in the case of program exposure or AE exposure, the switching gear is driven by a motor as in the first embodiment. Is also good.

In each of the above embodiments, the switching means is driven simultaneously when the shutter speed is selected. However, the switching means may be driven by a motor after the shutter is charged. In this case, when the winding of the film is not detected as described above, since the control circuit rotates the switching means in a direction to decrease the urging force of the drive lever spring, the urging force of the opening / closing lever spring decreases. Thus, the hoisting force required for shutter charging can be reduced. Further, in FIG. 4, the step motor 13 is controlled by the signal of the film winding detection unit 53. It goes without saying that the periods may be used in combination as appropriate.

[0026]

As described above, according to the present invention, the rotation speed of the opening and closing levers urged by the lever springs, that is, the curtain speed at the time of opening and closing the shutter opening changes according to the shutter speed. Therefore, the curtain speed on the low-speed side can be made slower than the curtain speed on the high-speed side, and camera shake at the start or stop of the sector can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a main part showing a first embodiment of a curtain speed adjusting mechanism of a camera shutter according to the present invention.

FIG. 2 is a configuration diagram of a main part showing a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a main part showing a third embodiment of the present invention.

FIG. 4 is a block diagram showing a control circuit of the present invention.

FIG. 5 is a configuration diagram showing a curtain speed adjusting mechanism of a conventional camera shutter.

[Explanation of symbols]

5, 15, 19, 25, 29 Supporting members 5a, 15a, 19a, 25a, 29a Spring-loaded boss 10 Worm 11, 12 Spur gear 13 Step motor 20, 30 Switching gear (switching means) 21 second dial 51 Photometric circuit section 52 Shutter speed setting unit 53 Film winding detection unit 54 Control circuit unit 55 Motor drive unit

Claims (2)

[Claims] 1. A sector drive lever for driving a sector to open and close a shutter opening, a sector drive spring for urging the sector drive lever in the opening and closing operation direction of the sector, and a locking end of the sector drive spring. And a switching means for moving the stationary position of the support member to an arbitrary position so as to change the urging force of the sector drive spring in accordance with the shutter speed. Curtain speed adjustment device. 2. The apparatus according to claim 1, wherein the switching means is operated in a direction to weaken the urging force of the sector drive spring before the film is wound, and the urging force of the sector drive spring corresponds to the shutter speed and is weakened after the film is wound. 2. The shutter speed adjusting mechanism for a camera shutter according to claim 1, wherein the switching unit is operated at an arbitrary position where the urging force becomes stronger than the urging force.