JP2509055B2 - Light-shielding blade for ultra-high-speed vertical-running focal plane shutter that exceeds 1/4000 second - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-shielding blade for an ultra-high speed, vertically running focal plane shutter whose maximum shutter speed exceeds 1/4000 second.

[0002]

2. Description of the Related Art Conventionally, a light-shielding blade used in a vertically running focal-plane shutter in which the light-shielding blade moves almost linearly has been required to move at a high speed in order to ensure the simultaneity of exposure in each part of a photographing screen. . For that purpose, it is possible to increase the amount of operating force as a first method, but in this case, the hoisting torque is increased in order to store the amount of force, and in the case of manual hoisting, the operator feels uncomfortable. In the case of electric winding, the power consumption of the motor is increased, which is not preferable. Further, since the impact force applied to the blade at the start or end of the exercise is large, it is disadvantageous in terms of durability.

As another method, it is conceivable to reduce the weight of the light shielding blade.

[0004]

However, it is difficult to maintain the mechanical strength such as the rigidity required for the light-shielding blades by making the carbon steel thin plate which has been conventionally used thinner than this, and further it is required to have a flat surface. It is also difficult to secure sex. Therefore, it has been attempted to reduce the weight by partially thinning the surface of the blade (that is, partially thinning the blade) without making the entire blade thin. However, in this case, since the surface is uneven, it is likely to cause stress concentration.
Further, when a shutter is constructed by using a plurality of such blades, there is a risk of light leakage to the overlapping portions of the blades.
In order to eliminate these drawbacks, a special device is required for combining and superposing the blades, which is troublesome in design and manufacturing. However, in order to operate the blade at high speed, it is essential to reduce its weight. Therefore, it is an object of the present invention that the surface is smooth, has a sufficient thickness to give the required mechanical strength, is light, and has a maximum shutter speed.
It is to provide a light-shielding blade for a vertically-running focal plane shutter capable of traveling at an ultra-high speed exceeding 1/4000 second.

A light-shielding blade capable of running at an extremely high speed with a maximum shutter speed exceeding 1/4000 second must satisfy four important properties: lightness, high bending rigidity, good flatness, and high durability. I have to. It is very difficult to find a single material that satisfies these properties at the same time.

[0006]

Therefore, the inventors of the present invention have focused their attention on the composite material, and as a result, have completed the present invention. That is, the present invention comprises "a skin layer portion, a core portion and a mirror-symmetrical laminated composite member of a skin portion, and the skin portion and the core portion each include a" resin layer internally reinforced with carbon fiber ", When the skin portion and the core portion are compared, the fiber directions of the both are substantially orthogonal to each other, and the fiber direction of the skin portion is substantially parallel to the longitudinal direction of the blade, which is more than 1/4000 second. We provide a light-shielding blade for ultra-high-speed, vertically-running focal plane shutters.

[0007]

In general, in order to reduce the weight, a material having a low density is used, and in order to further reduce the weight, a certain volume may be removed. Conventionally, titanium or plastic has been used as a material having a low density, but in the present invention, a resin reinforced with continuous fiber among carbon fibers having low density, high strength, and high elasticity (hereinafter, simply referred to as CFRP). Use). This CFRP is obtained by impregnating carbon fiber with a thermosetting resin such as epoxy resin or unsaturated polyester as a binder, and in the present invention, the carbon fiber / resin mixing ratio (Vol%) is 75%.
It is preferably about / 25 to 50/50. The specific gravity of CFRP in this range is 1.58 to 1.65, which is considerably smaller than that of titanium or aluminium, which is almost equivalent to that of a single plastic. The prepreg sheet, which is the precursor of CFRP, is carbon fiber impregnated with uncured B-stage resin. If a prepreg sheet with carbon fibers aligned in one direction is used, It is easy to obtain a hollow structure by cutting in the fiber direction into thin strips and arranging the strips at intervals.

In order to increase the flexural rigidity, the flexural rigidity is expressed by the product of the longitudinal elastic modulus E and the second moment of inertia Iz, so that E and Iz may be increased. Since E is a value peculiar to the material, naturally a material with a large E is desirable, and in this respect as well, carbon fiber is suitable because it is 200 to 350 GPa, which is twice as large as titanium. When using CFRP, for example, carbon fiber
E of 60% epoxy resin 40% in the fiber direction is larger than 150 GPa and that of titanium 110 GPa. However, E in the direction perpendicular to the fiber is 8 GPa, which is almost equal to the value of the epoxy resin itself. Therefore, the carbon fibers are not all arranged in one direction, and CFRP in which carbon fibers are crossed in two directions orthogonal to each other or in two directions not orthogonal to each other and CFRP arranged in any direction can also be used. However, when the light shielding blade is applied to a vertically running focal plane shutter, the shape of the blade is generally elongated and its longitudinal direction is perpendicular to the traveling direction of the blade. As a result of analyzing the motion of the blade with a high-speed camera, it was found that it is desirable to increase the bending rigidity of the blade in the longitudinal direction as compared with other directions. To meet this requirement, CFRP, which has anisotropy in bending rigidity, is suitable for material design.

In order to obtain even better flatness, the thermosetting resin is superior to the metal thin plate having internal stress.
Especially in the case of titanium blades used for high-speed shutters in the past, it is necessary to heat the thin titanium plate at high temperature in vacuum to improve the flatness, but in the case of thermosetting resin, it should be cured in the atmosphere. CFRP is also advantageous in this respect, since it is possible to easily obtain good flatness as it is.

Next, the present invention will be described in detail by way of examples (preferred embodiments) with reference to the drawings.

[0011]

EXAMPLE FIG. 1 is a partial sectional view of a light-shielding blade of this example.
FIG. 2 is a partial perspective view thereof. The blade of this embodiment has a five-layer structure, in which the skin portions (1a) and (1b) are made of CFRP having a thickness of, for example, 20 μm, while the core portion (2) is
The thickness of the strips arranged at regular intervals is, for example, 20 μm
CFRPs (2a) and (2c) and a central substrate (2b) sandwiched between them and having a thickness of, for example, 10 μm.
The central substrate (2b) has a large number of through holes (2b ₁ ),
These holes have the function of increasing the bonding strength of CFRP (2a) and (2b) bonded to both sides. That is, when the resin in the prepreg sheet or the separately applied adhesive is pressed, the resin on both sides may flow through this hole and be integrated. Further, in some cases, the through hole (2b ₁ ) may not be provided in order to give the central substrate (2b) a light-shielding property.

The directions of the carbon fibers in the CFRP are aligned with the longitudinal direction of the blade in (1a) and (1b), and are aligned at right angles to the longitudinal direction in (2a) and (2c). And (2
a) and (2c) have the same size. That is, the blade of this embodiment is mirror-symmetric with respect to the neutral axis. The reason for the mirror symmetry is to maintain the flatness of the blade. However, the hollow portion (3) may be designed to have different volumes in the longitudinal direction (see FIG. 6). This requires high strength in the vicinity of the position where it is connected to the arm that supports the blades, but the strength may become lower toward the tip, so it is useful when you want to enlarge the hollow part to make it as light as possible. .

As the material of the central substrate, a metal foil or a plastic film having a large number of hollow portions (3) penetrating therethrough is used. The metal that can be used is preferably a light metal, such as titanium, a titanium alloy, aluminum,
Aluminum alloy, beryllium, beryllium alloy and the like can be mentioned. Further, as the plastic, those having a large tensile strength are preferable, for example, celluloid, cellulose acetate, polyethylene, polypropylene, polyvinyl chloride,
Polystyrene, polyethylene terephthalate, polycarbonate, nylon and polyimide are used.

Although CFRP itself has a light-shielding property, if the CFRP itself is insufficient in the light-shielding property, a black pigment or carbon fine particles are added to the resin , the resin is dyed black, or CFRP is used. It is advisable to provide a black paint layer on the front surface or the back surface. Also, when manufacturing a light-shielding blade by punching into a predetermined shape, cutting the hollow part will make the end surface uneven, so in order to avoid it, design it beforehand so that the hollow part comes inside the required shape. Alternatively, it is also possible to fabricate the light shielding blade by first fabricating a member having a required shape and then laminating the members.

[Application Example] FIG. 3 shows the blade of the embodiment as a first blade (31), a second blade (39), a third blade (40), a fourth blade (41) and a fifth blade (42). FIG. 6 is an assembly diagram of a known vertical traveling type focal plane shutter applied as a. First blade (3
1) pins (32), (33) and arms (3)
4) and (35) are rotatably connected. Further, the arms (34) and (35) are rotatable about shafts (37) and (38) planted in the shutter substrate (36). Connect the pins (32) and (33) to the shafts (37) and (3
Since it forms a substantially parallelogram with 8), the first blade (31) translates in the longitudinal direction of the aperture (46) in accordance with the rotation of the arms (32), (33). However, the second blade (39), the third blade (40), the fourth blade (41) and the fifth blade (42) behave differently than the first blade. That is, the pin (43) planted on the first blade (31) is rotatably coupled to the second blade (39), and the arm (44) rotatably supported by the shaft (37). A cam groove (39a) that engages with the pin (45) planted in is provided in the base of the second blade (39). Therefore, the movement of the second blade (39) is determined by the movement of the pin (45) and the shape of the cam groove (39a) via the pin (43). The third blade (40) is rotatably supported by the shaft (38), and cam grooves (41a) and (42a) that engage with the pin (45) are provided at the bases thereof, respectively.
The pin (45) is also rotatably coupled to an arm (44) rotatably supported on the shaft (37), and
It rotates together with the arm (44) which rotates about 7). Cam grooves (39a), (40a), (41) of each blade
By the action of a) and (42a), when the first blade (31) is located above the aperture (46) in the figure, the blade is in a deployed state and covers the aperture,
When the first blade (31) retracts below the aperture (46), almost all the blades are overlapped. In this case, the third blade (40) to the fifth blade (4
Three blades up to 2) is rotated about the shaft (38), though, it operates to open and close the fan. In this type of focal plane shutter, another set of such blades is usually provided, and one of the blades is used as a shutter opening member and the other is operated as a shutter closing member.

As described above, in the vertical traveling type focal plane shutter, the movement of the blades after the second blade (39) is changed from the rotational movement about the shafts (37) and (38) to the cam groove. It is a translational motion converted through (39a) to (42a). Therefore, since the cam grooves (39a) to (42a) slide on the pin (45), the inner wall thereof is required to have wear resistance. Since the blades of the examples are mainly composed of carbon fibers, which have a low friction coefficient with metal of 0.2 and a low wear rate, they satisfy the above requirements sufficiently. Furthermore, the coefficient of thermal expansion of carbon fiber is extremely low at -0.8 x 10 ^-6 / ° C, making it an optimal material for cam grooves that require high dimensional accuracy.

FIG. 4 is a plan view of the first blade (31), and FIG. 5 is a sectional view taken along the line XY of FIG. (1a),
(1b) is a skin part, (2) is a core part, (3) is a hollow part,
(6) shows the implanted pin. The hollow portion (3) increases in volume as it moves away from the pin (6) as shown.
The through holes present in the central substrate of the core portion (2) is omitted in FIG.

FIG. 4 is a plan view of the first blade (31),
FIG. 5 is a sectional view taken along the line XY of FIG. (1a), (1
b) is a skin part, (2) is a core part, (3) is a hollow part,
(6) shows the implanted pin. The hollow portion (3) increases in volume as it moves away from the pin (6) as shown.
It should be noted that the through hole existing in the central substrate of the core portion (2) is the third a
It is omitted in the figure.

FIG. 6 shows the second blade (39) through the fifth blade (4).
FIG. 7 is a plan view of 2), and FIG. 7 is a sectional view taken along the line XY of FIG. (1a) and (1b) are skin parts, (2) is a core part,
(3) is a hollow part, (6) is a small hole for inserting a pin for connecting the arm for rotary motion and the blade, and (7) is a pin embedded in the arm. It is a cam groove that penetrates in the mating thickness direction. The hollow portion (3) increases in volume with increasing distance from the pin (6) and the cam groove (7).

It should be noted that the core portion (2) has a through hole existing in the central substrate.
The through holes are omitted in FIG. As described above, by applying the light-shielding blade of the embodiment to this application example, it is possible to realize a shutter blade that satisfies the basic properties described above that are lightweight and have high bending rigidity. In addition, flatness, dimensional stability, wear resistance, environment resistance, etc. were also satisfied.

[0021]

As described above, according to the present invention, it is possible to obtain a light-shielding blade which has a smooth surface and has sufficient mechanical strength and is light and capable of running at an ultrahigh speed of more than 1/4000 second. in addition,
Since it has high shock absorption, it can withstand the large acceleration that it receives at the end of high-speed driving, and the vibration generated at the time of impact due to the forced stop at the end of driving can be stopped quickly, so that the next shutter operation can be performed quickly. However, the blade does not come into contact with the angle of view (frame) or other blades, and thus the durability of the blade is improved.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view of a light shielding blade showing an embodiment of the present invention.

FIG. 2 is a partial perspective view of the light shielding blade shown in FIG.

FIG. 3 is an assembly view of a vertical traveling type focal plane shutter showing an application example.

FIG. 4 is a plan view of another shading blade.

5 is a sectional view taken along the line XY of FIG.

FIG. 6 is a plan view of another light shielding blade.

FIG. 7 is a sectional view taken along the line XY of FIG.

[Explanation of symbols]

 1a, 1b ... skin part 2 ... core part 3 ... hollow part

 ─────────────────────────────────────────────────── ─── Continuation of the front page Jury President Tomoyuki Nakamura Judge Judge Ryo Maruyama Judge Kimio Yoshino (56) References JP 54-52527 (JP, A) JP 49-84232 (JP, A) JP Sho 54-21477 (JP, A)

Claims (3)

(57) [Claims] 1. A laminated composite member comprising a skin portion, a core portion, and a skin portion, which are mirror-symmetrical in order, and each of the skin portion and the core portion includes a “resin layer internally reinforced with carbon fiber”. When the core part and the core part are compared, the fiber directions of the two parts are substantially orthogonal to each other, and the fiber direction of the skin part is substantially parallel to the longitudinal direction of the blade. -A light-shielding blade for a vertically running focal plane shutter. 2. The carbon fiber / resin mixing ratio (V
ol%) is in the range of 75/25 to 50/50. 3. The light-shielding blade according to claim 1, wherein the resin layer contains carbon fine particles.