JP2000338544A - Focal-plane shutter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the light shielding property of a focal-plane shutter. SOLUTION: In this focal-plane shutter equipped with a slit forming blade 9 and an auxiliary blade 13 supported by plural actuation arms 3 so that they can perform a parallel link motion, and plural covering blades 15 to 18 rocking around the shaft 6 of the arm 3 as the center, the light shielding property is made excellent by providing the respective blades in a state where they are successively partially superposed. The blade 9 is provided on actuation arms 3 and 5 by coupling pins 7 and 8 so that it can perform the parallel link motion, and an auxiliary arm 10 forms a level difference between one end coupled with the plural actuation arms and the other end coupled with the auxiliary blade 13, and simultaneously abuts on the lower surface of the pin 5 and the blade 13. Then, the blade 13 is provided on the back surface side of the blade 9 from the back surface of the arm 5 through the arm 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focal plane shutter.

[0002]

2. Description of the Related Art There are various types of recent focal plane shutters, one of which is as follows.
The operation arm is swung by the rotation of a motor provided on the shutter substrate, and a plurality of covering blades provided on a holding plate provided so as to face the rear surface of the substrate, a slit forming blade and an auxiliary blade interlocking with the plurality of covering blades. (For example, Japanese Utility Model Publication No. 54-6431).

FIG. 2 shows a conventional arrangement of shutter blades, in which a ray passage window 31a is closed by a shutter blade group provided on the front surface (upper surface of FIG. 2) of a shutter substrate 31. A drive arm 32 driven by a drive member such as a spring or an electromagnet (not shown) is provided on the rear side of the shutter substrate 31, and a drive pin 32 a provided on the drive arm has an arc hole of the shutter substrate 31. It penetrates and projects to the front side.

A shutter operation arm 33 for moving the shutter blade group is formed of a plate-like body having a rectangular shape in a plan view, and a tip on a short side is swung by a fulcrum pin 34 protruding from a shutter substrate. It is movably supported. Drive pin 32a
Engages with a long hole provided in the shutter operation arm 33 and can swing. A driven arm 35 having a similar shape is provided on the upper surface of the shutter substrate 31 so as to be swingable about a fulcrum pin 36 in parallel with the shutter operation arm 33. An auxiliary blade 37 having a substantially rectangular planar shape is interposed on the rear side of the two arms 33, 35, and the operating arm 33 is provided via pins 38, 38 protruding from the upper surface thereof. , 35 can be interlocked.

[0005] An auxiliary blade 39 is provided on the lower surface of the auxiliary blade 37 in a partially abutting state. The auxiliary blade 39 has a substantially rectangular planar shape.
By the swing of 35, it is possible to move vertically.
The auxiliary blade 39 is connected to the shutter operating arm 33 and the driven arm 35 by connecting pins 40,40. A slit forming blade 41 is provided on the lower surface of the auxiliary blade 39 so as to partially contact the auxiliary blade 39. The slit forming blade 41 is made of a substantially rectangular plate material having both ends positioned on both sides of the light passage window 31a. The slit forming blades 41 can be moved in parallel in the vertical direction on the paper according to the swing of these arms via the pins 42 provided on the arms 33 and 35.

On the lower surface of the auxiliary blade 37, in addition to the above-mentioned auxiliary blade 39, a first covering blade 43 is provided in a partially abutting state. A second covering blade 44 is provided on a lower surface side of the first covering blade 43, a third covering blade 45 is provided on a lower surface side of the second covering blade, and a second covering blade 45 is further provided on a lower surface side thereof. Four covering blades 46 are sequentially provided partially in contact with each other.
Each of the covering blades is formed of a U-shaped plate body having a different angle, and the end on the short side is swingably supported by a fulcrum pin 36 supporting the driven arm 35. The drive pin 32a of the drive arm 32 is inserted into the hole provided at the intermediate position.
Are engaged. Therefore, when the drive arm 32 swings, the covering blades 45 to 48 can simultaneously swing by the drive pin 32a.

As described above, the shutter blade group is composed of a combination of two auxiliary blades, slit forming blades, and four covering blades.
2 rotates clockwise around the fulcrum pin 34, these shutter blades move downward in the drawing, and
Exposure is completed by opening 1a and then closing the light passage window by a second shutter blade group (rear curtain) provided on the back side of the shutter substrate.

[0008]

As described above, the shutter blade group closes the light passage window in a state where the blades are partially in contact with each other. There is a problem that a closed state cannot be obtained. FIG. 2B shows a state in which the shutter blade groups are provided so as to overlap with each other. The auxiliary blade 37, the auxiliary blade 39, the slit forming blade 41, and the first blade are arranged in order from the top.
And four covering blades 43 to 46 are provided. However, since the first covering blade 43 is located on the lower surface of the slit forming blade 41, a gap corresponding to two blades is formed between the auxiliary blade 37 and the first covering blade. Since light leaks, the result is that light-shielding properties are reduced.

[0009]

In order to solve the above-mentioned problems, the focal plane shutter of the present invention is designed to improve the light shielding property by employing the following means. The focal plane shutter to which the present invention is applied is capable of closing the light passage window by sequentially partially overlapping the auxiliary arm, the slit forming blade, the auxiliary blade, and each of the covering blades below the first covering blade. is there. Since the slit forming blade is connected to the plurality of operating members via the coupling member and is located below the auxiliary member connected to the operating arm, the slit forming blade is provided with a height difference and one end is provided. The lower end of the operating member is in contact with the lower surface of the operating member, and the other end is in contact with the lower surface of an auxiliary arm provided to be in contact with the lower surface of the operating member. As described above, since the auxiliary arm has a height difference, one end portion is in contact with the lower surface of the operation arm, and the other end portion is capable of contacting the lower surface of the slit forming blade. Since the gaps between the members generated by the sequential overlapping are closed in this manner, the light shielding property is high.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A feature of the present invention is that a slit forming blade and an auxiliary blade supported so as to perform a parallel link motion by a plurality of operating arms, and a plurality of rotating blades rotating about the axis of the operating arm. The focal plane shutter having the covering blades described above is characterized in that the light shielding property is enhanced. The above-mentioned slit forming blade is provided on the operating arm by the first connecting member, and the auxiliary blades are provided by the third connecting member on the auxiliary member provided on the plurality of operating arms by the second connecting member. It should be possible to move without collision.

The above-mentioned auxiliary arm is provided with a height difference between one end where the slit forming blade overlaps with the operating arm and the other end where the slit forming blade is connected with the auxiliary blade, so that the lower surfaces of the operating arms having different heights are provided. It is desirable to connect both the upper arm and the upper surface of the auxiliary arm. The above-mentioned auxiliary blade is provided on the back side of the slit forming blade from the operating arm via the auxiliary arm, so that the slit forming blade, the auxiliary blade, and a plurality of covering blades from the auxiliary arm are sequentially overlapped. Is desirable.

[0012]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a main part of the configuration of a focal plane shutter according to the present invention. Contrary to FIG. 2A in which the arrangement of shutter blade groups shows a conventional example, slit forming blades and the like are shown in FIG. Are positioned so that the blades that perform the parallel link motion are located below, and the covering blades that are swinging are located above. A first operating arm 3 swings about a first shaft 4 on a drive pin 2 projecting from a drive arm (not shown) that swings by a drive motor provided on a camera body (not shown). It is provided. Below the first operating arm 3 in FIG. 1, a second operating arm 5 having a shape substantially similar to that of the first operating arm 3 is provided so as to be swingable about a second shaft 6.

The distal ends of the operating arms 3 and 5 are located near the center of the lower side of the light beam passing window 1a, and the distal ends of the operating arms 3 and 5 have connecting pins 7 and 8 as first connecting members. Are provided with slit forming blades 9. Slit forming blade 9
Is formed in a substantially rectangular shape slightly longer than the lateral width of the light beam passing window 1a, and can be moved in parallel in the vertical direction in the drawing by the swing of the operating arms 3 and 5. An auxiliary arm 10 formed in a wedge shape is in contact with a lower surface of a substantially central portion of each of the arms 3 and 5, and is connected to the two arms by connecting pins 11 and 12 which are second connecting members so as to be interlocked therewith. I have.

An auxiliary blade 13 is provided on the lower surface of the slit forming blade 9 so as to be partially in contact therewith. Auxiliary blade 13
Are also formed in a shape close to a rectangle slightly longer than the width of the light beam passing window 1a. The upper side near the left end of the auxiliary blade 13 is formed to be slightly wider, and the lower part of the auxiliary arm 10 contacts the widened portion. Then, this wide portion is fixed to a fixing pin 1 as a third coupling member.
4, 14 are connected to the auxiliary arm 10. Therefore, since the auxiliary blade 13 performs a parallel link motion, the auxiliary blade 13 can reciprocate in the vertical direction integrally with the auxiliary arm 10. On the lower surface of the auxiliary blade 13, a first covering blade 15 is provided.
Are provided in a partially abutting state. The first covering blade 15
The plane shape is formed like a bird's wing, and the tip is a light-passing window 1
It is only in the middle of a.

A second covering blade 16 is provided on the lower surface of the first covering blade 15 so as to be in partial contact therewith. The planar shape of the second covering blade 16 has a shape as if the first covering blade 15 is long, and the tip portion is beyond the right side of the light ray passing window 1a. A third covering blade 17 is provided on a lower surface of the second covering blade 16 in a partially abutting state with the third covering blade 17, and a fourth covering blade is similarly provided on a lower surface of the third covering blade 16. 18
Is provided. Each of the third covering blade 17 and the fourth covering blade 18 has a wide tapered flat end, and the front end of the third covering blade 17 and the fourth covering blade 18 can shield light passing through the right side of the light passing window 1a. There is.

Each of the four covering blades 15 to 18 has a second shaft 6 whose base supports the second operating arm 5.
And a hole provided at a predetermined distance from the support portion is engaged with the drive pin 2. Therefore, when the drive pin 2 rotates counterclockwise about the shaft 4 from the state shown in FIG. 1, the blades 9 and 13 that move in parallel link move in parallel, and the four swinging cover blades 15 to 18 move. By swinging counterclockwise about the second shaft 6 by a known method, it is also possible to move above the light beam passing window 1a. Note that two members drawn by imaginary lines from the left to the lower part of the shutter mounting plate 1 indicate the first operating arm 21 and the second operating arm 22 of the other shutter (rear curtain). .

FIG. 1B is an enlarged view of a main part of the above-mentioned shutter blade group and partially viewed from the side. As shown in the figure, the slit forming blade 9 and the auxiliary arm 10 are both connected via the connecting pins 8 and 12 to the second
Are connected to the lower surface of the operating arm 5. The slit forming blade 9 partially contacts the lower surface of the auxiliary arm 10 and is formed in a projecting shape so as to be able to contact the lower surface of the operating arm 5 with which the upper surface of the auxiliary arm is in contact. The height difference is provided.

Further, since the auxiliary arm 10 has a height difference, the auxiliary arm 10 partially contacts the lower surface of the second operating arm 5 and is driven by the second operating arm 5 via the connecting pins 11 and 12. It is possible. At the same time, the auxiliary blades 13 are partially overlapped with the auxiliary arm, so that the auxiliary blades 13 are fixed to each other by the fixing pins 14 as the third connecting members.

This focal plane shutter employs an auxiliary arm 10 so that the blades can be sequentially stacked. For this reason, the shutter blades overlap the slit forming blades 9, the auxiliary blades 13, and the covering blades 15 to 18 in this order. If the auxiliary blades 13 are arranged below the slit forming blades 9 and are connected to the operating arms 3 and 5 via the connecting pins 11 and 12, the connecting pins 11 and 12 hinder the movement of the slit forming blades 9. It cannot work well as a shutter. For this reason, an auxiliary arm 10 is provided so as not to hinder the movement of the slit forming blade 9, and the operating arms 3, 5 and the auxiliary blade 13 are connected to bypass the slit forming blade 9. The auxiliary arm 10 is a slit forming blade 9
A height difference 10a corresponding to the thickness of the slit forming blade 9 is provided in order to detour. In this manner, the slit forming blade 9, the auxiliary arm 10, and the auxiliary blade 13 sequentially overlap without any gap, and also overlap with the first covering blade 15 without any gap, so that a shutter having a high light shielding property is obtained.

[0020]

According to the present invention, the height of the auxiliary arm and the slit-forming blades is different, or the auxiliary blades are provided on the back side of the slit-forming blades. They can be provided in an overlapping state. This allows a structure in which no gap is formed between the arms and the blades to improve the light shielding properties of the focal plane shutter.

[Brief description of the drawings]

FIG. 1A is a plan view of a main part, and FIG. 1B is a cross-sectional view showing a state where an arm and a blade overlap each other.

FIG. 2A is a plan view of a main part of a conventional example, and FIG. 2B is an explanatory view showing a state in which an arm and a blade overlap each other.

[Explanation of symbols]

 3,5 Operating arm 4,6 axis 7,8 First connecting member (connecting pin) 9 Slit forming blade 10 Auxiliary arm 11,12 Second connecting member (connecting pin) 13 Auxiliary blade 15-18 Covering blade

Claims (1)

[Claims] 1. A focal plane comprising: a slit forming blade and an auxiliary blade supported so as to perform a parallel link motion by a plurality of operation arms; and a plurality of covering blades rotating about an axis of the operation arm. In the shutter, the slit forming blade is provided on the operating arm by a first connecting member, and the auxiliary blade is provided by a third connecting member on an auxiliary arm provided on the plurality of operating arms by a second connecting member. The auxiliary arm has a height difference between one end connected to the operation arm and the other end connected to the auxiliary blade, and the auxiliary blade is formed with the slit from the operation arm via the auxiliary arm. A focal plane shutter provided on the back side of the blade.