JP2002296641A - Focal plane shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To constitute a driving part of the second closing lever not to be displaced in the direction of a thickness of a board. SOLUTION: A closing blade is driven by a closing lever and an opening blade is driven by an opening lever so as to close and open an aperture 10 provided in the board 1. The closing lever comprises the first and second levers 21, 22. The second closing lever 22 is supported by the first closing lever 21 and a coaxial shaft 1b and can follow the first closing lever 21. The driving part 22b for driving the closing blade is provided at an end of the second closing lever 22. A pipe 22c provided at a pivot is fitted to the shaft 1b. The first closing lever 21 fits a pipe 21c provided at the pivot to the pipe 22c. The pipes 21c, 22c rotatably support each other. The displacement of the driving part 22b in the direction of the thickness of the board 1 is regulated by the both pipes when the second closing lever 22 swings. A step 1d is provided on the shaft 1b. A flange 21d provided in the pipe 21c abuts on the step 1d. The displacement of the first closing lever 21 in the direction of the shaft is regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camera shutter, and more particularly to a camera shutter in which an opening operation of an exposure control means is performed by an opening blade and a closing operation is performed by a closing blade.

[0002]

2. Description of the Related Art A shutter for controlling exposure by an open blade and a closed blade holds a driving force of an opening lever and a closing lever for performing an opening operation and a closing operation by an electromagnet, and turns off the current of the electromagnet. Thus, the opening operation and the closing operation are performed, and the exposure control is performed by changing the timing of turning off the open discharge magnet and the closing electromagnet.

In the case of a focal plane shutter of a double light shielding type, when the setting is completed, both the closing blade and the opening blade are spread to close the shutter opening doubly.
By the release operation, the closing blade first retreats from the shutter opening, then the opening blade retreats to open the shutter opening to expose, after a predetermined time elapses, expands the closing blade, closes the shutter opening, ends the exposure, and further performs a reset operation. The shutter blade opening is double-closed to return to the setting completion state.

FIGS. 2 and 3 show a specific structure of the related art. An opening 10 is provided in a substrate 1. A set lever 30 is swingably fitted to the shaft 1a on the substrate 1, and a protruding portion 30a of the set lever 30 is used to set a first closing lever 25 described later in a setting completed state. The projection 30b is provided for setting an opening lever 23 described later to a setting completion state. The center pipe 26c of the first closing lever 25 and the second closing lever 26 is rotatably fitted to the shaft 1b erected on the substrate 1. The first closing lever 25 is urged clockwise (hereinafter, referred to as “clockwise”) by a pitch-wound drive spring 20 (shown in FIG. 3). The second closing lever 26 is urged by a tension spring 41 in a counterclockwise (hereinafter, referred to as “left-handed”) direction via the arm 40a.

Further, a semi-cylindrical pin 25b is projected from the first closing lever 25, and the side of the second closing lever 26 abuts on the pin 25b.
Can follow the first closing lever 25. Similarly, a center shaft portion 23a of an opening lever 23 is swingably fitted to a shaft 1c (shown in FIG. 2) on the substrate 1, and is urged clockwise by an opening spring (not shown). Second closing lever 2
The drive pins 26b and 23b provided at the respective ends of the release lever 6 and the release lever 23 penetrate through the arc-shaped through holes 1d and 1e provided in the substrate 1 and protrude below the substrate 1, and the drive pin 26b Arms 40a and 40b of the closing blade unit
Are connected to the main arm 40a of the
b is connected to the main arm of the open blade unit (not shown). The main arm 40a is urged leftward by a tension spring 41. The main arm of the open blade unit is urged clockwise by a drive spring (not shown).

FIG. 2 shows a state where the setting is completed. The driving pin 26b is located at the lower end of the through hole 1d to close the opening 10 by expanding the closing blade.
3b is located at the upper end of the through hole 1e and closes the opening 10 by expanding the open blade. In this state, the soft magnetic plate 25c provided on the first closing lever 25 is attracted to the closing electromagnet 11 fixed to the substrate 1 and the second closing lever 2
6 is held by a lock lever (not shown) so that the driving pin 26b is positioned at the lower end of the through hole 1d against the urging force of the tension spring 41. Also,
The soft magnetic plate 23 c provided on the open lever 23 is attracted to the open discharge magnet 12 fixed to the substrate 1. In this manner, the opening 1 is opened by expanding the closing blade and the opening blade.
0 is doubly closed and the position is maintained in the set completion state.

Further, since the first closing lever 25 and the second closing lever 26 make different swinging movements, it is not preferable that the frictional force affects each other. Therefore, as shown in FIG.
and an intermediate pipe 26c is provided between the central shaft portion 26a and the central shaft portion 26a.
d is interposed so that frictional force does not affect each other. Center hole 2 of first closing lever 25
A washer 25d is arranged on the upper surface around 5a, a driving spring 20 is interposed in a compressed state between the washer 25 and a ratchet wheel 24 provided at the upper end of the shaft 1b, and the first closing lever 25 is urged clockwise. are doing. On the lower surface of the first closing lever 25, a roller 25e is provided at a position where the set lever 30 is driven.

[0008]

In such a conventional structure, the center hole 25a of the first closing lever 25 is fitted in the intermediate pipe 26c only in the axial direction by the thickness of the plate. In the central shaft portion 26a of the second closing lever 26, the length in the axial direction is short, and there is a slight clearance between the center shaft portion 26a and the intermediate pipe 26c, so that the distal ends of the first closing lever 25 and the second closing lever 26 Each of them is displaced in the thickness direction of the substrate 1. In particular, as the tip of the second closing lever 26 is farther away from the axis, the displacement amount of the substrate 1 in the thickness direction increases, so that the closing blade unit, which is the driven member, is correctly driven by the driving pin 26b. There is a problem that it has an undesirable effect on That is, there is a variation in driving for each frame during photographing, and an error in exposure time due to a difference in the attitude of the camera during photographing. Further, since the intermediate pipe 26c and the washer 26d are interposed in order to minimize the influence of the frictional force between the two levers, the number of parts increases and the assembly becomes complicated. Was.

In view of the above, the present invention has a structure in which the driving portion of the second closing lever is not displaced in the thickness direction of the substrate without requiring extra parts and without complicating the assembly.
Provided is a focal plane shutter in which a closing blade unit as a driven member is driven by a correct operation.

[0010]

SUMMARY OF THE INVENTION A focal plane shutter according to the present invention comprises a closing lever for driving a closing blade for opening and closing an opening provided on a substrate, and an opening lever for driving an opening blade for opening and closing the opening. ing. The closing lever comprises a first closing lever and a second closing lever, and the second closing lever is coaxially swingably supported together with the first closing lever, and is capable of following the first closing lever. A driving portion for driving the closing blade is provided at a tip end of the first closing lever. The second closing lever is rotatably supported by fitting a pipe portion provided at the swing center portion to a shaft, and the first closing lever is rotatable. Is rotatably supported by fitting a pipe portion provided at the swing center portion to the pipe portion of the second closing lever, and the two pipe portions allow the substrate of the drive unit to rotate when the second closing lever swings. It is characterized in that displacement in the thickness direction is regulated. With this configuration, the displacement of the driving portion of the second closing lever in the thickness direction of the substrate is restricted, and the closing blade unit, which is the driven member, can be driven by a correct operation. And posture differences are unlikely to occur.

A step is formed on the shaft, and a flange is formed at the tip of the pipe portion of the first closing lever so as to contact the step and restrict the movement of the first closing lever in the axial direction. It is characterized by having. With this configuration, it is possible to prevent the first closing lever from pressing down on the second closing lever and hindering the mutual movement due to the thrust biasing force of the pitch-wound drive spring that drives the first closing lever. Works.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an enlarged view showing a configuration of a closing lever in a focal plane shutter according to the present invention. The configuration other than the closing lever of the shutter driving unit described with reference to FIG. 2 and the configuration of the closing blade and the opening blade (not shown) driven by this driving unit are substantially the same in the present invention. And the description is omitted.

As shown in FIG. 1, the first closing lever 21 and the second closing lever 22 of the present invention are concentrically rotatably supported on the shaft 1b. That is, the center hole 22a, which is the swing center of the second closing lever 22, is fitted to the shaft 1b, and the pipe portion 22c extends upward around the center hole 22a to be fitted to the shaft 1b. I have. The center hole 21a, which is the swing center of the first closing lever 21, is fitted into the pipe 22c, and the pipe 21c is moved upward with the center hole 21a as the center.
Extends and is fitted to the pipe portion 22c.

The shaft 1b is a stepped shaft, and a step 1d is formed at the upper end of the shaft 1b. A flange 21d is formed at the distal end of the pipe 21c so as to abut the step 1d and face the distal end surface of the pipe 22c. A slight clearance is provided between the distal end surface of the pipe portion 22c and the flange portion 21d. For this reason, the movement of the first closing lever 21 in the axial direction (in particular, the direction of the second closing lever 22) is regulated by the step 1d, and the pressing force from the drive spring 20 wound around the tip of the pipe 22c at a pitch is used. Has no effect. With this configuration, even if a thrust direction force from the drive spring 20 acts, the force does not act on the second closing lever 22 and the first closing lever 21
It is possible to prevent the closing lever 22 from being pressed down and hindering each other's movement. Further, even if a torsional moment is generated in the second closing lever 22 when the second closing lever 22 rotates counterclockwise due to the urging force of the tension spring 41, the pipe portion 2
The second closing lever 22 can be smoothly rotated with a small amount of displacement in the plate thickness direction because the 2c is long fitted to the shaft 1b.

A semi-cylindrical positioning pin 21b protrudes from the first closing lever 21, and the side surface of the second closing lever 22 abuts on the positioning pin 21b. Is the same as that in FIG. A drive pin 22b is provided at the tip of the second closing lever 22, and penetrates through the arc-shaped through hole 1d provided in the substrate 1 and protrudes below the substrate 1, and is provided between the arms 40a and 40b of the closing blade unit. The configuration for driving the closing blade by connecting to the main arm 40a is the same as that in FIG. A soft magnetic plate 21e is provided on the upper surface of the first closing lever 21. The soft magnetic plate 21e is attracted to the closing electromagnet 11 fixed to the substrate 1, and the second closing lever 22 is a lock lever (not shown). The driving pin 2 against the urging force of the tension spring 41.
The configuration in which 2b is held so as to be positioned at the lower end of the through hole 1d is the same as that in FIG. Also, the first closing lever 2
A closing spring 20 fitted to the pipe portion 21c is interposed in a compressed state between the upper surface of the shaft 1 and a ratchet wheel 24 provided at the upper end of the shaft 1b, and biases the first closing lever 21 clockwise. The configuration to be performed is the same as that in FIG. The roller 21
f is substantially the same as the roller 25e of FIG.

According to the present invention having such a configuration, when the release switch is pressed from the setting completion state of the double light blocking state and the locking of the second closing lever 22 by the lock lever is released, the second closing lever 22 is released. Rotates counterclockwise by the spring force of the tension spring 41 and contacts the center surface of the positioning pin 21b and stops. During this time, the second closing lever 22 rotates around the pipe portion 22c which is long in the axial direction, so that the driving pin 22
b can greatly reduce displacement in the thickness direction of the substrate 1. Further, the pressing force from the first closing lever 21 does not act on the second closing lever 22 by the step 1d. For this reason, the second closing lever 22 can smoothly turn left in a correct posture. When the opening time is closed by the closing blade after the exposure time is completed, the energization of the closing electromagnet 11 holding the soft magnetic plate 21e of the first closing lever 21 is stopped. Therefore, the attraction force to the soft magnetic plate 21e disappears, the first closing lever 21 turns clockwise by the urging force of the closing spring 20, and the second closing lever 22 also turns clockwise following the first closing lever 21. Then, the drive pin 22b moves to the lower end of the through hole 1d, so that the closing blade closes the opening 10 and the photographing for one frame ends. During this time, the rotation of the drive pins 22b in the plate thickness direction of the substrate 1 is significantly smaller than in the related art because the drive pins 22b rotate around the pipe portions 21c and 22c that are long in the axial direction. Therefore, the closing blade can be driven correctly, and there is no variation or an error in exposure time.

[0017]

According to the present invention, the first closing lever and the second closing lever swing about the pipe provided at the swing center, so that the driving portion of the second closing lever is mounted on the substrate. There is little displacement in the thickness direction, and the closed blade unit, which is a driven member, can be driven by a correct operation.
There is no variation in driving for each frame and no error in exposure time. Also, since a step is provided on the shaft to restrict the movement of the first closing lever in the axial direction, the first
Due to the thrust biasing force of the drive spring that drives the closing lever, the first closing lever can prevent the second closing lever from pressing down and hindering the movement of each other. In addition, the number of parts does not increase, and no complicated assembly is required.

[Brief description of the drawings]

FIG. 1 is an enlarged sectional view showing a configuration of a closing lever which is a main part of a focal plane shutter according to the present invention.

FIG. 2 is a front view showing a setting completion state of a conventional shutter driving mechanism.

FIG. 3 is an enlarged sectional view showing a configuration of a conventional closing lever.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 1b Axis 1d Step 10 Opening 21 First closing lever 21c Pipe 21d Collar 22 Second closing lever 22b Second closing lever drive 22c Pipe

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H081 AA19 AA20 AA21 AA28 AA31 BB01 BB26

Claims (2)

[Claims] A closing lever that drives a closing blade that opens and closes an opening provided in the substrate; and an opening lever that drives an opening blade that opens and closes the opening, wherein the closing lever includes a first closing lever and a second closing lever. A second closing lever, wherein the second closing lever is coaxially swingably supported together with the first closing lever and is capable of following the first closing lever. A drive unit for driving a closing blade is provided, and the second closing lever is rotatably supported by fitting a pipe portion provided at a swing center portion to the shaft, and the first closing lever is The pipe portion provided at the swing center portion is rotatably supported by fitting the pipe portion of the second closing lever to the pipe portion, and the drive is performed by the two pipe portions when the second closing lever swings. Part of the substrate A focal plane shutter, wherein the displacement of the lens in the thickness direction is restricted. 2. The axial direction of the first closing lever according to claim 1, wherein a stepped portion is formed on the shaft, and a tip of the pipe portion of the first closing lever comes into contact with the stepped portion in the axial direction of the first closing lever. A focal plane shutter, characterized in that a brim portion for restricting the movement of the focal plane is formed.