JP3052437B2 - Focal plane shutter - Google Patents

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 which is disposed near an exposure window (aperture) of a camera and has a front curtain and a rear curtain each composed of four or five divided blades.

[0002]

2. Description of the Related Art In recent years, there has been a demand for a higher shutter speed of a camera for reasons such as an increase in film sensitivity and a desire for a new image expression. Provided.

In order to increase the shutter speed, it is necessary to increase the driving force of the shutter driving system or to reduce the weight of the shutter blades. However, if the driving force is increased, there are problems such as a shortage of the capacity of a battery serving as a power source of the drive system and an earlier time for replacing the battery, which makes general application difficult. Therefore, attempts have been made to reduce the weight of the blades of the shutter.

[0004] As a problem associated with weight reduction, there is a balance with rigidity required for the blade. In other words, if the thickness of the blade is reduced for the purpose of weight reduction, the rigidity of the blade itself decreases,
When the shutter is running or stopped, a phenomenon occurs in which the blades undulate. This wave travels in the longitudinal direction of the blade. If the blades are wavy, or if the next shutter operation is performed while the blades are wavy, there is a problem that the blades or the blades and the storage frame that determines the angle of view collide, causing damage to the blades and the like. Therefore, members constituting the blades of the shutter are required to be lightweight and highly rigid.

As materials satisfying such requirements, various blade members for shutters made of so-called (carbon) fiber reinforced plastic (CFRP) have been proposed (for example, Japanese Patent Application Laid-Open No. Sho 59-61827, Japanese Utility Model Application Laid-Open No. Sho 61-61827). 60-63
825, JP-A-62-199439, JP-A-63-17435, etc.).

The blade members of the shutter disclosed in these publications are composed of a continuous fiber of carbon fibers aligned in one direction and a reinforced resin intermediate layer made of a matrix resin containing the same, and a carbon fiber aligned in one direction. It is composed of continuous fibers of fibers and a reinforced resin surface layer made of a matrix resin containing the fibers, and the intermediate layer and the surface layer are laminated to form a blade member. At this time, the surface layer is arranged such that its fibers are substantially parallel to the longitudinal direction of the shutter blades, and the intermediate layer is arranged such that its fibers are substantially orthogonal to the longitudinal direction of the shutter blades. The effect of suppressing the waving phenomenon and increasing the rigidity is obtained by the intermediate layer.

However, carbon fiber reinforced plastics, unlike metal materials, are not flexible even if they are made of a thin plate, and it is difficult to correct them once formed by warping. Must be sufficiently flat. For this reason, the yield tends to decrease as the shape of the divided blades increases. Therefore, in the conventional focal plane shutter, considering that the shape of the divided blades tends to increase as the amount of movement decreases, up to the second divided blade counted from the largest amount of movement is made of carbon fiber reinforced plastic. The other divided blades were made of aluminum alloy sheets.

[0008]

However, recently,
There is a demand for an ultra-high-speed shutter that is faster than 1/8000 second. Therefore, in the conventional focal plane shutter using carbon fiber reinforced plastic, it is necessary to further reduce the weight of the blade member to be driven, but this is not easy in view of yield and the like. On the other hand, when the speed of the shutter is increased by increasing the driving force of the driving system, the blade member is damaged, and there is a problem in its durability.

An object of the present invention is to reduce the weight by 1 /
An object of the present invention is to provide a focal plane shutter capable of realizing a shutter speed exceeding 8000 seconds.

[0010]

The present invention will be described with reference to FIGS. 1 and 4 showing one embodiment.
The front curtain 10 and the rear curtain 20 each composed of one or five divided blades 11 to 14 and 21 to 24, and these divided blades 11
And drive mechanisms 19 and 29 for moving 〜14, 21 to 24 from the state folded outside the exposure window 30a to the state expanded to cover the exposure window 30a, or from the expanded state to the folded state. It is applied to the provided focal plane shutter. According to the first aspect of the present invention, at least a third one of the divided blades 11 to 14 and 21 to 24 is counted in descending order of the movement amount.
3 are formed of a composite material, and the composite material is composed of carbon fibers 1 and 5 laminated in a plane symmetry and matrix resins 2 and 6 including the carbon fibers 1 and 5 and carbon fibers 1 and 2 of the surface layer 3 and the intermediate layer 7.
The direction of 5 is a fiber reinforced plastic which is almost orthogonal.
Along with the moving amount of the divided blades in descending order.
Thickness of the third and subsequent blades 13-14, 23-24 counted
With the largest and second moving blades 11 to 12, 21
The above-mentioned object is achieved by forming the substrate to have a thickness of at least 22 .

[0011]

The divided blades 11 to 14 and 21 to 24 made of a high-rigidity and lightweight fiber-reinforced plastic are used in at least the third order in the order of the moving amount, so that the conventional structure can be used without sacrificing the rigidity. The overall weight of the shutter described above can be reduced, and it is possible to cope with an ultra-high-speed shutter. In addition, by using the third fiber-reinforced plastic, the blade waving phenomenon that occurs when the blade is running and when the blade is stopped is immediately attenuated. Therefore, for example, it was possible to confirm for the first time that the mutual interference between the blades was small and the running performance was very stable as compared with the case where the third sheet was made of an aluminum alloy at a shutter speed of 1/8000 second or more .
Furthermore, the shape of the higher the split vane 11-14 the amount of movement of the split vane 11 through 14 and 21 through 24 is small tends to be increased, an increase in the size of the shape of the vane deterioration of the yield of the composite material Leads to. Therefore, since the thickness of the composite material constituting the divided blades having the larger shape, that is, the third and subsequent blades 13 to 14 and 23 to 24 counted in descending order of the movement amount is increased, the yield is improved.

In the means and means for solving the above problems which explain the constitution of the present invention, the drawings of the embodiments are used for easy understanding of the present invention. However, the present invention is not limited to this.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. 1 to 3 are front views showing one embodiment of a focal plane shutter according to the present invention.

In these figures, reference numerals 10 and 20 denote a front curtain and a rear curtain, respectively, which constitute a focal plane shutter. The front curtain 10 includes four divided blades 11 to 14, 21
To 24. Reference numerals 15 and 16 denote arms, respectively.
Are rotatably connected to the shafts X ₁ , X ₂ implanted in the shaft.
The above-mentioned divided blades 11 to 14 are respectively connected to the arms 1 by caulking pins 17 _{1 to} 17 ₄ and 18 ₁ to 18 _4.
5, 16 are rotatably connected. Note that arm 1
A drive shaft 31 is attached to the hole 16a of the sixth, and receives a driving force from a well-known shutter driving device to open and close the front curtain 10 when the shutter is driven.

Similarly, the rear curtain 20 has four divided blades 21 to 21.
24. Reference numerals 25 and 26 denote arms, respectively. The arms 25 and 26 are rotatably connected to axes X ₃ and X ₄ implanted on the shutter substrate 30. ,
Then, the above-mentioned split vane 21 to 24, the arm 2 respectively by caulking pins 27 _{1-27 4} and 28 ₁ to 28 ₄
5, 26 are rotatably connected. Note that arm 2
A drive shaft 32 is attached to the hole 26a of the sixth, and receives a driving force from a well-known shutter driving device to open and close the rear curtain 20 when the shutter is driven.

As described above, in this embodiment, the arms 15, 16, 25, and 26, the axes X _{1 to} X ₄ , and the caulking pin 1
7, 18, 27, 28, and drive shafts 31, 32, drive mechanism 1 for moving divided blades 11 to 14, 21 to 24, respectively.
9, 29 are constituted.

In this embodiment, up to the third divided blades counted in descending order of the moving amount, that is, the divided blades 11 to 13 and the divided blades 21 to 23 are mainly made of carbon fiber reinforced plastic (CFRP). The other divided blades 14 and 24 are formed of a composite material, and are formed of a known aluminum alloy.

FIGS. 4 and 5 show the composite material.
As shown in the figure, a reinforced resin intermediate layer 7 composed of carbon fiber continuous fibers or short fibers 5 aligned in one direction and a matrix resin 6 containing the same, and unidirectional carbon fiber continuous fibers 1 and a matrix resin 2 containing the same.
And the surface material layer 3 are laminated such that the longitudinal directions of the carbon fibers 1 and 5 are substantially orthogonal to each other, and have a plate thickness of 50 to 120 μm. Incidentally, carbon black 4 may be added to the matrix resin 2 or 6 of the intermediate layer 7 or the surface material layer 3.

As the material of the reinforced resin constituting the intermediate layer 7 and the surface material layer 3, a prepreg sheet (prepreg) obtained by impregnating the precursors of the matrix resins 2 and 6 with carbon fibers 1 and 5 is used.
regsheet).

The prepreg sheet is a resin material obtained by impregnating a reinforcing fiber with a thermosetting resin liquid (for example, an uncured liquid of an epoxy resin or unsaturated polyester) which is a precursor of the matrix resin 2 or 6. In a B-stage state (a state where the composition is solidified and has no apparent fluidity, but can be finally cured by heating).

In order to obtain the composite material of this embodiment, a thickness of 10 to
A prepreg sheet having a thickness of about 60 μm
, And at least two sheets on the surface layer 3 sandwiching it, so that the longitudinal directions of the carbon fibers 1 and 5 of the intermediate layer 7 and the surface layer 3 are substantially orthogonal to each other, and the thickness direction of the composite material. May be laminated so as to be plane-symmetric with respect to the central axis of the above, and then heated and pressed to harden the resin liquid.

Each of the intermediate layer 7 and the surface material layer 3 may be formed by laminating a plurality of (for example, 2 to 5) prepreg sheets instead of one prepreg sheet. in this case,
The prepreg sheets may be laminated in the mid layer 7 or the surface layer 3 such that the fiber directions are alternately orthogonal to each other or parallel (in the same direction). For example, one prepreg sheet is used for the surface layer 3 and two prepreg sheets are used for the intermediate layer 7 so that the fiber direction is perpendicular to the prepreg sheet (the two sheets have fiber directions parallel to each other). You may.

The carbon fibers 5 used for the intermediate layer 7 may be short fibers because the carbon fiber 5 is the intermediate layer 7, and the fiber length is 1 to 1.
30 mm, especially about 5 to 15 mm, is suitable. The carbon fibers 1 and 5 preferably have a diameter of about 3 to 10 μm for both continuous fibers and short fibers.

[0024]

When the light-shielding properties and the surface lubricity are insufficient, carbon black may be added to the prepreg sheet as described above. Carbon black may be added in an amount of about 5 to 15% by weight based on the resin liquid (solid content of 100 parts by weight). The average particle size of the carbon black is preferably 0.07 μm or less. Carbon black may be added only to the surface material layer 3 or may be added only to the mid layer 7.
Each has its own unique characteristics.

When the laminated prepreg sheet is hot-pressed, a composite material as shown in FIGS. 4 and 5 is obtained. At this stage, the surface is painted black (dry loop painting).
May be applied. This coating is performed for the purpose of improving light-shielding properties, lowering surface reflectivity, improving appearance and appearance, and improving surface lubricity. The thickness of the coating film is suitably from 0.1 to 10 μm, but if the thickness is reduced to about 0.1 to 3 μm, the risk of warpage of the composite material is reduced.

The composite material thus obtained is divided into divided blades 11
To 14 or 21 to 24 (the longitudinal direction of the carbon fiber 5 of the intermediate layer 7 is divided blades 11 to 1).
4, 21 to 24) so as to be substantially perpendicular to the longitudinal direction of the divided blades 11 to 14, 21
~ 24 are obtained. Thereafter, the above-described black coating may be applied.

Next, the operation of the focal plane shutter of this embodiment will be described. FIG. 1 is a diagram illustrating a state in which the front curtain 10 is expanded and the exposure window (aperture) 30a is closed. That is, the divided blades 11 to 14 are deployed to close the exposure window 30a, and the divided blades constituting the rear curtain 20 are retracted upward from the exposure window 30a and folded.

The driving force from the shutter driving device is the arm 1
Once transmitted to the drive shaft 31 which is attached to 6, the arm 16 is rotated in the clockwise direction in FIG. 1 about the axis X _2. As a result, the front curtain 10 starts to open and exposure starts. After a predetermined time, the driving force from the shutter driving unit is transmitted to the drive shaft 32 attached to the arm 26, the arm 26 is rotated in the clockwise direction in FIG. 1 about the axis X _4. As a result, the second curtain 20 becomes the first curtain 1
Exposure is performed while following 0 and forming a slit having a predetermined width between the divided blades 11 and 21. In other words, the opened front curtain 10 is closed, and the closed rear curtain 20 is expanded. At the end of the exposure, as shown in FIG. 3, the rear curtain 20 is unfolded to close the exposure window 30a, and the front curtain 10 is retracted under the exposure window 30a. FIG. 2 shows the first curtain 10
FIG. 5 is a diagram showing a state where the rear curtain 20 is retracted from the exposure window 30a, and the shutter speed is in a state of a valve (B).

Next, the operation and effect of the present invention will be described based on experimental examples. -Experimental Example 1-(1) First, carbon fibers (average diameter 6 to 7 µm) are aligned in one direction by continuous fibers, the matrix resin is an epoxy resin, and the resin content is 35 to 45% by weight. Thickness
A prepreg sheet A of 20 to 40 μm was prepared.

(2) Next, a carbon fiber (average diameter 6 to 7 μm)
m) is a short fiber with a length of 1 to 30 mm, aligned in one direction, the matrix resin is an epoxy resin, and the resin content is
60 to 75% by weight, 10 to 50 μm thick prepreg
Sheet B was prepared. This sheet is manufactured by a centrifugal pulling method applying papermaking technology.

(3) Two sheets A and one sheet B are prepared as described above, and the fiber direction is 0 ° (surface layer) / 90 ° (intermediate layer) / 0 ° (surface layer). And three sheets are symmetrically laminated such that the type of sheet is A (surface layer) / B (intermediate layer) / A (surface layer), and 5 to 15 kg at a temperature of 130 ° C. / Cm ² and apply 1-2
The epoxy resin was cured by allowing it to stand for a time, and then slowly cooled to room temperature to obtain a composite material having a thickness of 50 to 120 μm.

(4) From one composite material having good flatness, 20 to 50 divided blades were manufactured by press punching. At this time, punching was performed so that the direction of the carbon fibers in the intermediate layer was orthogonal to the longitudinal direction of the divided blades.

(5) A dry loop coating was applied to both front and back surfaces of each of the plurality of divided blades having a good flatness to a thickness of 4 μm on each side to produce coated divided blades.

(6) The divided blades with the coating thus obtained are divided into divided blades 11 to 13, 21 to 23 shown in FIGS.
The focal plane shutters shown in FIGS. 1 to 3 were manufactured using aluminum alloy blades for the split blades 14 and 24.

Comparative Example A divided vane with a coating manufactured in the same manner as in Experimental Example 1 is shown in FIGS.
Used for the divided blades 11, 12, 21, 22 shown in FIG. 3,
The focal plane shutters shown in FIGS. 1 to 3 were manufactured by using aluminum alloy blades for the divided blades 13, 14, 23, and 24.

With respect to the shutters of Experimental Example 1 and Comparative Example, a durability test was conducted in which the time required for one blade to move up and down an angle of view of 24 mm (hereinafter referred to as a running speed) was varied to continuously raise and lower this angle of view. Was carried out. Table 1 shows the results.

[Table 1]

A running speed of 2.9 msec for an angle of view of 24 mm corresponds to an actual shutter speed of 1/8000 second, and a running speed of 2.5 msec corresponds to an ultra-high shutter speed of 1/8000 second or more. The shutter of the experimental example had much better durability than the shutter of the comparative example, and was particularly remarkable at an ultra-high shutter speed exceeding 1/8000 sec.

Experimental Example 2 A prepreg sheet A ′ was prepared by adding 10% by weight of carbon black having an average particle diameter of 0.01 μm or less to 100 parts by weight of resin in the prepreg sheet A used in Experimental Example 1. Hereinafter, a composite material, divided blades, and coated divided blades were sequentially manufactured in the same manner as in Experimental Example 1 except that sheet A ′ was used instead of sheet A.

Experimental Example 3 A prepreg sheet B ′ prepared by adding carbon black having an average particle diameter of 0.01 μm or less to the prepreg sheet B used in Experimental Example 1 by 10% by weight per 100 parts by weight of the resin was prepared. Hereinafter, a composite material, divided blades, and coated divided blades were sequentially manufactured in the same manner as in Experimental Example 1 except that sheet B ′ was used instead of sheet B.

Experimental Example 4 Two prepreg sheets A and two prepreg sheets B used in Experimental Example 1 were used.
The sheets are prepared such that the fiber direction thereof is 0 ° / 90 ° / 90 ° / 0 °, and the sheet type is A /
The layers were laminated symmetrically in a plane so as to have B / B / A, and a composite material was manufactured in the same manner as in Experimental Example 1. This composite material
The intermediate layer is composed of two sheets B. Thereafter, in the same manner as in Experimental Example 1, divided blades and painted divided blades were sequentially manufactured.

[0042]

[0043]

Experimental Example 5 Carbon fibers (average diameter 6 to 7 μm) are aligned in one direction by continuous fibers, and the matrix resin is an epoxy resin.
A prepreg sheet B ″ having a thickness of 10 to 50 μm was prepared. Next, a composite material, a split blade and a prepreg sheet B ″ were used in the same manner as in Experimental Example 1 except that the prepreg sheet B ″ was used instead of the prepreg sheet B. Painted split blades were manufactured.

The focal plane shutters shown in FIGS. 1 to 3 were manufactured by using the divided blades with the coatings of the above-mentioned Experimental Examples 1 to 5 for all of the divided blades 11 to 14 and 21 to 24 shown in FIGS. . When this focal plane shutter was subjected to the same high-speed shutter durability test as described above at a traveling speed of 2.5 msec, durability performance of 150,000 times or more was obtained, and sufficient high-speed stability and high-speed traveling performance were proved. In addition, the divided blades with the coating of Experimental Examples 2 to 5 are used for the divided blades 11, 12, 13, 21, 22, and 23 shown in FIGS. 1 to 3, and the divided blades 14 and 24 are made of aluminum alloy. When the focal plane shutter shown in FIGS. 1 to 3 was manufactured by using the above method, a durability performance of 150,000 times or more was similarly obtained at a running speed of 2.5 msec, and sufficient high-speed stability and high-speed running were proved.

According to the experimental results of the inventor, FIGS.
In the four-piece shutter shown in FIG. 3, the three divided blades 11 to 13 and 21 to 23 having a large moving amount are formed of a composite material only, and the divided blades 11 to 14 and 21 to 24
There is no great difference in the durability performance itself when compared with the case where is entirely formed of a composite material, and in any case, an ultra high-speed shutter exceeding 1/8000 second can be realized. Similarly, according to the experimental results of the present inventor, even in a five-sheet shutter, the case where three divided blades with a large moving amount are formed of a composite material and the case with three or more blades, that is, four with a large moving amount, are used. Even when the divided blades or all the divided blades are formed of a composite material, there is no significant difference in durability performance itself.
It is possible to realize an ultra-high-speed shutter exceeding 00 seconds.

According to the experimental results of the present inventor, the third and subsequent blades counted in descending order of the moving amount have a thickness of 1 / th even if they are thicker than the two blades having the larger moving amount. It was found that a high-speed shutter of over 8000 seconds could be realized, and that there was no need to reinforce the drive mechanism, and the durability was sufficient.

That is, as described above, since the yield of the fiber-reinforced plastic becomes worse as the shape becomes larger, the divided blade having a relatively large shape (FIG.
With respect to the divided blades 13, 14, 23, 24), application of fiber reinforced plastic has been refrained. However, if the sheet thickness is increased to prevent warpage, sufficient flatness can be obtained, a yield above a certain level can be secured, and fiber reinforced plastic can be applied to more (extremely all) divided blades. Will be possible. The problem here is whether it is necessary to strengthen the drive mechanism to increase the weight of the blades with the increase in the plate thickness. It has become clear from the experimental results of the present inventor that it is not necessary to greatly increase the strength of the film. Therefore, there is no possibility of causing a phenomenon such as damage to the blade due to an increase in the driving force, and sufficient durability performance can be secured.

This is a very important problem when the thickness of the two blades having a large moving distance is reduced in order to reduce the weight of the shutter. That is, in the conventional shutter, when increasing the speed, the two blades having a large movement amount to withstand the impact are thickened to increase the rigidity, and the other blades having a small movement amount are required. Was thinner with an aluminum alloy to reduce the weight a little, but conversely, increasing the thickness does not cause a problem in athletic performance, but rather, these blades should be made of fiber-reinforced plastic. This leads to the realization of an ultra-high-speed shutter exceeding 1/8000 second.

The details of the focal plane shutter of the present invention are not limited to the above-described embodiment, and various modifications are possible. As an example, the composite material constituting the divided blade is not limited to the one described in the embodiment, and a well-known fiber reinforced plastic may be used.

[0051]

As described above in detail, according to the present invention, the material for forming the divided blade can be reduced by only slightly changing the material.
It is possible to realize an ultra-high-speed shutter exceeding / 8000 seconds. In addition, since the fiber direction is substantially perpendicular to the plane-symmetric laminated structure, anisotropy can be effectively obtained. That is, by directing the fiber in the longitudinal direction of the blade, the rigidity is improved, and the blade blur can be more effectively attenuated, whereby high-speed stability and high-speed running performance can be achieved. In addition, the divided blade having a large shape,
The multiple blades that constitute the third and subsequent blades counted from the largest momentum
Since the thickness of the composite material is increased, the yield of the divided blades can be improved and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a view showing one embodiment of a focal plane shutter according to the present invention, and is a front view showing a state in which a front curtain is unfolded and covers an exposure window.

FIG. 2 is a front view showing a state where a front curtain and a rear curtain are retracted from an exposure window.

FIG. 3 is a front view showing a state where a rear curtain is unfolded and covers an exposure window.

FIG. 4 is a cross-sectional view illustrating an example of a configuration of a composite material.

FIG. 5 is a cross-sectional view showing another example of the configuration of the composite material.

[Explanation of symbols]

 1, 5 Carbon fiber 2, 6 Matrix resin 3 Surface material layer 4 Carbon black 7 Intermediate layer 10 Front curtain 11 to 14, 21 to 24 Divided blade 15, 16, 25, 26 Arm 17, 18, 27, 28 Caulking pin 19 , 29 Drive mechanism 20 Rear curtain 30 Shutter substrate 30a Exposure window 31, 32 Drive axis X axis

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Masayuki Kanemuro 1-6-3 Nishioi, Shinagawa-ku, Tokyo Nikon Oi Works Co., Ltd. (56) References JP-A-63-17435 (JP, A) Sho 60-63825 (JP, U) Actual opening Sho 60-135727 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03B 9/08-9/54

Claims (1)

(57) [Claims] 1. A front curtain and a rear curtain each composed of four or five divided blades, and a state in which these divided blades are folded out of the exposure window to a state in which they are expanded to cover the exposure window, or A focal plane shutter having a drive mechanism for moving from an unfolded state to a folded state, wherein the divided blades are formed of a composite material at least up to a third one in the descending order of the amount of movement. composite materials are a matrix resin include carbon fibers and this laminate in plane symmetry, the direction of the carbon fibers in the surface layer and the intermediate layer Ru fiber reinforced plastic der that is substantially perpendicular
At the same time, the divided blades
Subsequent blade thickness is the maximum and second blade
A focal plane shutter formed so as to have a thickness greater than or equal to the thickness of the shutter.