JP2002214671A - Focal plane shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a closing blade unit as a driven member to be driven by correct operation by making the driving part for a 2nd closing level constituted so as not to be displaced along the thickness of a substrate. SOLUTION: An opening 10 is bored in the substrate 1, a closing blade which opens and closes the opening 10 is driven by 1st and 2nd closing levers 21 and 22, and an opening blade which opens and closes the opening is driven by a release lever 23. The closing lever and release lever are set at specific positions by a set lever 30. The 2nd closing lever 22 is supported so that it can freely swing on a shaft 1b together with the 1st closing lever 21, and is enable to follow the 1st closing lever 21. A driving pin 22b driving the closing blade is provided at the tip part of the 2nd closing lever 22. The substrate 1 is provided with a restriction part 1f which restricts the displacement of the 2nd closing lever 22 toward the thickness direction of the substrate 1 when the 2nd closing lever 22 is in a position where the closing blade is retracted from the opening 10.

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 (front curtain) and a closing operation is performed by a closing blade (rear curtain).

[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 the double light shielding type, both the closing blade and the opening blade close the shutter opening in the initial state. After retreating, the shutter opening is opened and exposure is performed. After a predetermined time elapses, the closing blade is widened to close the shutter opening to complete the exposure, and further, the opening blade is closed by a reset operation to return to the initial state.

FIG. 6 and FIG. 7 show a specific structure of the related art, in which 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 protrusion 30a of the set lever 30 is for setting a first closing lever 21 described later to an initial position. ,
The protrusion 30b is for setting an opening lever 23 described later to an initial position. The shaft 1 b erected on the substrate 1 has a central shaft portion 21 of a first closing lever 21 and a second closing lever 22.
a and 22a are swingably fitted respectively. The first closing lever 21 is urged clockwise (hereinafter referred to as “clockwise”) by a closing spring (not shown). Then, the spring 41 is connected to the second closing lever 2 via the arm 40a.
2 is urged counterclockwise (hereinafter referred to as "left-handed").

Further, a semi-cylindrical pin 21b is protruded from the first closing lever 21, and the side of the second closing lever 22 abuts on the pin 21b, so that the second closing lever 22
Can follow the first closing lever 21. Similarly, a central shaft portion 23a of an opening lever 23 is swingably fitted to the shaft 1c on the substrate 1, and is urged in a clockwise direction by an opening spring (not shown). A drive pin 22b provided at each end of the second closing lever 22 and the opening lever 23,
23b are arc-shaped through holes 1d, 1e provided in the substrate 1.
, And protrudes below the substrate 1, and the driving pin 22 b
It is connected to the main arm 40a of the arms 40a and 40b of the closed blade unit, and the drive pin 23b is connected to the main arm of the open blade unit (not shown). The main arm 40a is urged leftward by a spring 41.
The main arm of the open blade unit is urged clockwise by a spring (not shown).

FIG. 6 shows a state where the setting is completed. The driving pin 22b is located at the lower end of the through hole 1d, and the opening 10 is closed by a closing blade.
The opening 10 is closed by spreading the open blades at the upper end of e. In this state, the soft magnetic plate 21c provided on the first closing lever 21 is attracted to the closing electromagnet 11 fixed to the substrate 1, and the second closing lever 22 is locked by a lock lever (not shown). , Tension spring 41
Is held at the lower end of the through hole 1d at the position described above. The soft magnetic plate 2 provided on the release lever 23
3 c is attracted to the open discharge magnet 12 fixed to the substrate 1. In this manner, the position is held in the setting completed state in which the opening 10 is closed by expanding the closing blade and the opening blade.

Further, since the first closing lever 21 and the second closing lever 22 make different swinging motions, it is not preferable that the frictional force affects each other. Therefore, as shown in FIG.
a, 22a, and a central shaft portion 21c.
A washer 22d is interposed between a and the central shaft portion 22a so that frictional force does not affect each other. The blade receiving plate 5 is located below the main arm 40a, and the open and closed blades (not shown) are located between the arm and the blade receiving plate 5.

[0008]

In such a conventional structure, the central shaft portion 21a of the first closing lever 21 is fitted to the shaft 1b within a long range in the axial direction. Is hardly displaced in the thickness direction of the substrate. On the other hand, the second closing lever 2
2, the axial length is short, and the shaft 1b
Since there is a slight clearance between the second closing lever 22 and the center shaft portion 22a (the driving pin 22b
And the like), there is a problem that the farther from the axis 1b, the larger the displacement amount of the substrate in the thickness direction, which has an unfavorable effect on correctly driving the closed blade unit as the driven member. In other words, there is a variation in driving for each frame during photographing, an error in exposure time due to a difference in attitude of the camera during photographing, and the like. In order to minimize friction between the levers, the collar 2
Since the 2c and the washer 22d are interposed, there is a problem that the number of parts increases and the assembly becomes complicated.

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]

According to the present invention, there is provided a focal plane shutter comprising: a closing lever for driving a closing blade for opening and closing an opening provided on a substrate; an opening lever for driving an opening blade for opening and closing the opening; In a focal plane shutter including a closing lever and a set lever for setting the opening lever to a predetermined position, the closing lever includes a first closing lever and a second closing lever, and the second closing lever is the second closing lever. A driving unit for driving the closing blade is provided at a tip end of the second closing lever, the driving unit being provided so as to be swingable coaxially with the first closing lever, and capable of following the first closing lever. Is
When the second closing lever is at a position where the closing blade is retracted from the opening, a regulating portion for regulating displacement of the second closing lever in a thickness direction of the substrate is provided. I have. Since the board has a regulation part,
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 a driven member, can be driven by a correct operation.

The regulating portion is preferably formed integrally with the substrate, so that the number of components does not increase and the assembly is not complicated.

[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 of a drive unit of the focal plane shutter according to the present invention, and illustration of a closed blade, an open blade, and the like driven by the drive unit is omitted. In addition, since substantially the same components as those described with reference to FIG. 6 are denoted by the same names and reference numerals, description thereof will be omitted.

FIG. 1 shows a setting completion state of a double-shielded type focal plane shutter according to the present invention. The first closing lever 21 has a central shaft portion 21a fitted to the small diameter portion of the stepped shaft 1b, and is in the left-handed position as in the case of FIG.
1 c is attracted to the closing electromagnet 11. The second closing lever 22 has a central shaft portion 22a at a large diameter portion of the stepped shaft 1b.
Are fitted to each other, and are in a position of swinging clockwise about the shaft 1b. The second closing lever 22 is a tension spring 41
Is biased in the counterclockwise direction with respect to the first closing lever 21 by the spring force, but is locked in a lock lever (not shown), so that it is in the clockwise position against the spring force and has a through hole 1d. Is held on the lower side of the drawing. To this end, a drive section (drive pin) 22b provided at the tip of the second closing lever 22
As a result, the closing blade is driven in the direction of expanding the blade via the arms 40a and 40b of the closing blade unit to close the opening 10. The opening lever 23 is in a left-handed rotation position around the axis 1c, and the driving blade 23b drives the opening blade through the arm of the opening blade unit in a direction in which the blade is spread to close the opening 10. The soft magnetic plate 23 c provided on the opening lever 23 is attracted to the open discharge magnet 12. In this manner, in the setting completion state shown in FIG. 1, the closing blade and the opening blade are both widened and held at the position where the opening 10 is closed, and the first closing lever 21 is at the left-handed position and the spring force is charged. Have been.

A restricting portion 1f is formed on the substrate 1 near the upper end of the through hole 1d and integrally with the substrate 1. As shown in FIG. 2, the restricting portion 1 f
The closing lever 22 is formed in a shape extending above the driving portion 22b. For this reason, at the position where the second closing lever 22 swings counterclockwise due to the spring force of the tension spring 41, the second closing lever 22 is located in a state of invading the lower surface of the restricting portion 1f. Even if the shaft portion 22a is fitted only in a short range in the axial direction of the shaft 1b, the driving portion 22b at the tip cannot be displaced in the thickness direction of the substrate 1 and always stops at an appropriate position. Further, the shaft 1b is a stepped shaft, the central shaft portion 21a of the first closing lever 21 is fitted to the small diameter portion, the central shaft portion 22a of the second closing lever 22 is fitted to the large diameter portion, The configuration is such that one rocking motion does not affect the other.

As shown in FIG. 3, when the second closing lever 22 is pulled by the tension spring 41 and approaches the first closing lever 21, the relative positions of the two closing levers are equal to the positioning pins 21b of the first closing lever 21. The second closing lever 22 is positioned by contact with the side surface of the second closing lever 22. That is, the positioning pin 21b protruding downward from the first closing lever 21 is formed in a semi-cylindrical shape, and has a
The mutual positions are determined by the side surfaces of the closing lever 22 abutting.

When the release switch of the camera (not shown) is pressed from the setting completion state of the double light shielding state shown in FIG. 1, the set lever 3 is driven by a motor (not shown).
0 turns counterclockwise to the state shown in FIG. Since the lock lever (not shown) releases the lock of the second closing lever 22 by the left rotation of the set lever 30, the second closing lever 22 rotates left by the spring force charged in the extension spring 41.
Due to this left rotation, as shown in FIG.
Side comes into contact with the center plane of the positioning pin 21b of the first closing lever 21 and stops. Further, as shown in FIG. 2, the driving section 22b at the tip of the second closing lever 22 is provided with a regulating section 1f.
And the displacement of the substrate 1 in the thickness direction is restricted. At this time, the position of the first closing lever 21 is the same as the position in FIG. 1 because the soft magnetic plate 21c is still attracted to the closing electromagnet 11. The same applies to the position of the release lever 23. For this reason, in the state of FIG. 4, the closing blade is retracted from the opening 10 and is folded, and the opening blade is expanded and the opening 10 is closed. That is, the state is a single light-shielded state only by the open blades, which means a state before exposure.

When energization of the open discharge magnet 12 is stopped in the state shown in FIG. 4, the attraction force to the soft magnetic plate 23c disappears, the release lever 23 turns clockwise by the biasing force of the spring, and the drive pin 23b is moved through the through hole 1e. , And as a result, the open blade is retracted from the opening 10 and folded.
In addition to the fact that the closing blade has already been retracted from the opening 10 and folded in the state of FIG. 4, this state means that the opening 10 is in an exposure state in which the opening is open.

Since both the closing blade and the opening blade are folded and retracted from the opening, the opening is completely opened, and after a predetermined time, the energization of the closing electromagnet 11 is stopped. For this reason, the attraction force to the soft magnetic plate 21c disappears, and the first
The closing lever 21 turns clockwise by the biasing force of the spring. Since the second closing lever 22 is also engaged by the pin 21b, it is pushed by the first closing lever 21 and turns clockwise against the spring force of the tension spring 41. Then, the drive pin 22b moves to the lower end of the through hole 1d, so that the closing blade is spread and the opening 10 is closed. Exposure is completed by opening the closing blade and closing the opening 10, and one frame of imaging is completed. This figure 5
Indicates that the opening 10 is closed by the closing blade, and the opening blade is still retracted from the opening 10 and is in a state immediately after the exposure operation while being folded.

Thereafter, in order to set the member at the set completion position in FIG. 1, the set lever 30 starts to turn clockwise.
At this time, the projection 30a of the set lever 30 rotates the first closing lever 21 counterclockwise, and the projection 30b pushes the projection 23d of the opening lever 23, thereby rotating the opening lever 23 counterclockwise. During this, a lock lever (not shown) is rotated to engage with the second closing lever 22, and the second closing lever 22 is moved by the tension spring 41.
Is prevented from following the leftward rotation of the first closing lever 21. In this way, the first closing lever 21 and the opening lever 23 are rotated leftward by the clockwise rotation of the set lever 30 and are attracted by the closing and opening discharge magnets 11 and 12, respectively, thereby returning to the setting completed state shown in FIG.

In this embodiment, the restricting portion 1f is provided with the through hole 1
d is provided only in the vicinity of the upper end of d. This is because the present invention is an exposure start area in the case where the slit width formed by the open blade and the closed blade is small in the exposure operation. Since it is particularly effective against variations in driving, a regulating portion 1f is provided in the exposure start area. However, the restricting portion may be provided over the entire operation range of the second drive lever 22.

In this embodiment, the tension spring is attached to the arm, but the tension spring is connected to the first closing member and the second closing member.
The second closing member may be configured to apply a left-handed biasing force to the closing member.

[0022]

According to the present invention, since the restricting portion is provided on the substrate, the driving portion of the second closing lever is restricted from being displaced in the thickness direction of the substrate. Driving can be performed by operation, and variations and attitude differences in driving for each frame are unlikely to occur. Further, when the regulating portion is formed integrally with the substrate, the number of components does not increase, and the assembly is not complicated.

[Brief description of the drawings]

FIG. 1 is a front view showing an initial state of a shutter driving mechanism in a focal plane shutter of the present invention.

FIG. 2 is an enlarged cross-sectional view illustrating a regulating portion of a second closing lever.

FIG. 3 is an enlarged sectional view illustrating a configuration of positioning a second closing lever.

FIG. 4 is a front view showing a state before exposure.

FIG. 5 is a front view showing a state immediately after the exposure operation.

FIG. 6 is a front view showing an initial state of a conventional shutter drive mechanism.

FIG. 7 is an enlarged cross-sectional view illustrating a shaft support portion of a conventional closing lever.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 1f Restriction part 10 Opening 21 First closing lever 22 Second closing lever 22b Driving part of second closing lever 23 Opening lever 30 Set lever

Claims (2)

[Claims] 1. A closing lever that drives a closing blade that opens and closes an opening provided on a substrate, an opening lever that drives an opening blade that opens and closes the opening, and positions the closing lever and the opening lever at predetermined positions. A setting lever for setting, wherein the closing lever comprises a first closing lever and a second closing lever; the second closing lever is coaxially swingably supported with the first closing lever; A drive unit for driving the closing blade is provided at a tip end of the second closing lever, the second closing lever retreats the closing blade from the opening on the substrate. A focal plane shutter provided with a restricting portion for restricting the displacement of the second closing lever in the thickness direction of the substrate when the substrate is in the position. 2. The focal plane shutter according to claim 1, wherein the restricting portion is formed integrally with the substrate.