JPH0423249B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a double-return type focal plane shutter in which the picture frame is covered with a leading curtain and a trailing curtain before and after the shutter is set.

Conventional double-return type focal plane shutters operate in the following steps: camera release → mirror up → shutter release → rear curtain start position return → front curtain start → rear curtain start → front curtain start position return, and mirror down. . However, the first curtain had to be started after waiting approximately 70 seconds for the bouncing when the second curtain returned to its starting position to completely subside, resulting in a huge loss of time.

Therefore, it is an object of the present invention to provide a double-return type focal plane shutter that shortens the time from the camera release to the start of the front curtain. do. FIG. 1 shows the shutter curtain opening/closing mechanism of the focal plane shutter according to the present invention after the shutter is set, and FIG. 2 shows the mirror drive mechanism at this time, where 1 is the substrate, 2 is the picture frame, and 3
4 is a pillar, 4 is a front curtain drive arm which is pivotally mounted on a shaft 5, is imparted with left rotation by a spring 6, and has a pin 7 implanted therein; 8 is supported on the front curtain drive arm 4 by a shaft 8a; A leading curtain actuating arm locking lever 9, which is given left rotation by a cage spring 8b, has a pin 10 (not shown) for supporting the leading curtain, forms an engaging portion 9a, and is pivotally connected to the shaft 5. A leading actuating arm 1 that is given dextrorotation by a spring 11;
2 is a leading curtain locking lever which is pivotally connected to a shaft 13 and provided with left rotation by a spring 19, but is prevented from turning to the left by a stopper 18; 14 is pivotally connected to a shaft 15 and provided with left rotation by a spring 16; The X-contact lever 17 shown is an X-contact. 20 is axis 2
A release lever 24 is pivotally connected to a shaft 25 and is given dextrorotation by a spring 23, but its right rotation is prevented by a stopper 22. A second mirror interlocking lever 27, whose left rotation is prevented by the stopper, is pivoted to a shaft 28 and is supported by a spring 2.
9 imparts levorotation, and the pin 30
The trailing curtain drive arm 31 supports a trailing curtain (not shown) and has a pin 32 that engages with the trailing curtain drive arm 27, and is pivotally connected to the shaft 28 and rotates dextro-rotated by a spring 33. a trailing curtain actuating arm 34 which is pivotally mounted on a shaft 35 and is given left rotation by a spring 36, but a trailing curtain locking lever 3 whose left rotation is prevented by a stopper 37;
Reference numeral 8 designates a mirror first moving lever which forms arm portions 38a and 38b, is pivotally connected to a shaft 39, and is imparted with right-handed rotation by a spring 40, but whose right-handed rotation is prevented by a stopper 41. Also the second
In the figure, 42 is a mirror box side plate in which pins 43 and 45 are installed, and 49 is formed on the side plate by a spring 46 that is pivotally connected to a shaft 44 fixed to the side plate 42 and supported by the pins 43 and 45. A mirror 50 imparted with dextrorotation via a pin 48 protruding through a hole 47 is pivoted to a shaft 51 and has an arm portion 50a, a surface 50b, and a bent portion 52. A spring 53 is stretched between the control lever 50 and a charge lever, which will be described next, so as to impart dextrorotation to the control lever. Reference numeral 54 forms a hook portion 54a, and the charge lever is pivotally connected to the shaft 51 and given left rotation by a spring 60. Reference numeral 55 inhibits the charge lever by engaging with the hook portion 54a of the charge lever 54. a second locking lever which has a bending portion 55a, which is pivotally connected to a shaft 56, is given dextrorotation by a spring 57, and which can be engaged with the second mirror interlocking lever 24;
Reference numeral 58 forms a bent portion 58a and an arm portion 58b, and is pivotally connected to a shaft 59, and is provided with left rotation by a spring 61, but the left rotation is prevented by a pin 62, and the mirror first moving lever 38 a first locking lever that can be engaged with the first locking lever;

The focal plane shutter according to the present invention constructed as described above operates as follows. That is,
After the shutter is set as shown in FIGS. 1 and 2, the second mirror interlock lever 24 is moved by the spring 26.
Since it is imparted with levorotatory properties, it is in contact with the stopper 22 and is separated from the second locking lever 55 on the side surface of the mirror box. Further, the mirror first moving lever 38 is given dextrorotation by the spring 40, so that it is in contact with the stopper 41, and is separated from the first locking lever 58 on the side surface of the mirror box. At this time, the first locking lever 58
The bent portion 58a is the arm portion 50 of the control lever 50.
Since the surface 50b of the control lever 50 contacts the pin 48 of the mirror 49 at the position shown in FIG. 2, the control lever 50 contacts the pin 48 of the mirror 49. Mirror 49 is therefore in the down state.

Next, when returning to the trailing curtain start position shown in FIGS. 3 and 4, the release lever 20 is unlocked and the trailing curtain operating arm 31 is rotated to the right by the tension of the spring 33, as shown in FIG. It is brought to the position. Therefore, the trailing curtain is returned to the starting position. At the same time, the arm portion 38a of the mirror first moving arm 38 is pushed by the trailing curtain operating arm 31, and the mirror first moving arm 38 is rotated to the left.
The arm portion 38b is the arm portion 58 of the first locking lever 58.
By pushing b, the first locking lever 58 is rotated to the right. Therefore, the control lever 50 is unlocked and rotated to the right by the tension of the spring 53 until its bent portion 52 abuts the charge lever 54. In this way, the surface 50b of the control lever 50
8, the mirror 49 is raised counterclockwise against the tension of the spring 46, which is selected to have a lower tension than the spring 53.

Thereafter, when the leading curtain locking lever 12 is turned to the right (for example, in conjunction with the raising movement of the mirror or controlled by an electromagnet), the leading curtain actuating arm 9, which has been released from the restraint, locks the leading curtain actuating arm. The front curtain is rotated to the left by the tension of the spring 6 via the lever 8, and the front curtain releases the image frame 2, and exposure is started.

After the appropriate exposure time has elapsed, the trailing curtain locking lever 34 is rotated to the right by a known means, and the trailing curtain drive arm 27, which has been released from inhibition, is rotated to the left by the tension of the spring 29 together with the trailing curtain actuating arm 31. The second curtain thus covers the image frame 2 and the exposure is completed. At this time, the second mirror interlocking lever 24 is moved to the rear curtain drive arm 2.
7, the second locking lever 55 is rotated to the left.
Therefore, the charge lever 54, which has been released from restraint, is rotated to the left by the tension of the spring 60, which causes the control lever 50 to be rotated to the left, so that the mirror 49 is returned to the down state. Further, the final stage operation of the trailing curtain drive arm 27 causes the X contact lever 14 to turn to the right, and the inhibition of the leading curtain operating arm 9 is released. The first curtain is rotated to cover picture frame 2. The picture frame is thus covered by both the leading and trailing curtains. The engagement relationship between the leading actuating arm 9 and the leading driving arm is released by the leading actuating arm locking lever 8 coming into contact with the pillar 3 and being rotated to the right in the final stage of the counterclockwise rotation movement. ing. Here, right rotation of the leading actuating arm 9 is inhibited because its engaging portion 9a engages with the bent portion 14a of the X contact lever 14.

This completes one shooting operation, but when the film is further wound up, the charge lever 54 is turned to the right, but the control lever 50 is
0a is in contact with the bent portion 58a of the first locking lever, so when the spring 60 is charged, the charge lever 54 is restrained by the second locking lever 55 and becomes the state shown in FIG. Further, in conjunction with the film winding operation, the leading curtain drive arm 4 and the trailing curtain drive arm 27 are each rotated to the right and set in the charge state shown in FIG.

As described above, according to the present invention, the operation process of the camera is as follows: camera release → rear curtain return to start position → mirror up → front curtain start → rear curtain start →
Since the configuration is such that the leading curtain returns to the starting position and the mirror is down, in order to release the mirror up lock at the final stage when the trailing curtain returns to the starting position,
The operating speed at the final stage of returning to the trailing curtain start position is reduced. Therefore, the magnitude of the bounce becomes smaller. In addition, since the bounce completely settles during the mirror up process, the approximately 70 〓 time required for the bounce to settle, which was conventionally required, is no longer required. This has the effect of greatly shortening the time from camera release to the start of the first curtain.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the shutter curtain opening/closing mechanism after the shutter is set in an embodiment of the focal plane shutter according to the present invention, FIG. 2 is a diagram showing the mirror up/down mechanism in the embodiment according to FIG. 1, and FIG. FIG. 4 is a diagram similar to FIG. 1 showing the state after the trailing curtain start position of the embodiment shown in FIG. 1 has been returned, and FIG. 4 is a diagram showing the mirror up and down mechanism in the same state as FIG. DESCRIPTION OF SYMBOLS 1... Board, 2... Image frame, 4... Leading curtain drive arm, 8... Leading curtain operating arm locking lever, 9... Leading curtain operating arm, 12... Leading curtain locking lever, 14...
...X contact lever, 17...X contact, 20... Release lever, 24... Mirror second interlocking lever, 2
7... Trailing curtain drive arm, 31... Trailing curtain operating arm, 34... Trailing curtain locking lever, 38... Mirror first moving lever, 42... Mirror box side plate, 4
9... Mirror, 50... Control lever, 54... Charge lever, 55... Second locking lever, 58...
...First locking lever.

Claims (1)

[Claims] 1. The front curtain and the rear curtain cover the image frame before and after the shutter is set, and after the rear curtain is returned to the starting position, the front curtain is started to start exposure. In the double-return type focal plane shutter, which opens and closes the trailing curtain by reciprocating action, the trailing curtain operating arm is biased by a spring toward the trailing curtain start position; a release lever that locks the curtain operating arm at a position where the rear curtain covers the image frame and releases the lock in conjunction with the camera release; a mirror that can take a down position and an up position; and a mirror that works in conjunction with the mirror. and a control lever biased in a direction to raise the mirror when the mirror is in the down position; a locking member that is pushed and moved by the operating trailing curtain operating arm to release the locking of the control lever; A focal plane ivy characterized by its ability to move.