JPH09171206A - Focal-plane shutter for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shutter equipped with an overcharge absorbing mechanism capable of reducing the number of parts, reducing cost and saving space by producing a main arm pivotally supporting plural blades of synthetic resin in special form. SOLUTION: The main arm 13 and an auxiliary arm 14 pivotally supporting a rear blade group 12 are pivotally attached to a shutter bottom board 1. The main arm 13 is made of synthetic resin, and a depressing part 13b, a lock and contact part 13c and an elastic part 13d are formed at the vicinity part of the pivotally attached part. The elastic part 13d energizes the depressing part 13b to the lock and contact part 13c side so that the driving pin 5b of a rear blade driving member 5 is interposed by the depressing part 13b and the lock and contact part 13c. In charging operation, the main arm 13 abuts on a stopper 1n and the elastic part 13d is deformed to absorb the overstroke component of the driving pin 5b.

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 for a camera including a front blade group and a rear blade group each having a plurality of blades pivotally supported by a plurality of arms.

[0002]

2. Description of the Related Art This type of focal plane shutter is
Usually, the arm of each blade group and the driving member are constituted by different members, and their charging operation is performed by the setting member in conjunction with the film winding. In that case,
The force of the set member is first transmitted to the drive member, and the force of the drive member is transmitted to the main arm of the blade group.However, due to the dimensional tolerance of each component, etc.
Since it is difficult to manufacture them so that they operate exactly in accordance with the desired operation amount, in practice, the set member is
Originally, it should be possible to operate (overstroke) more than the operation amount necessary to operate the drive member, and the drive member should be designed to operate more than the operation amount necessary to operate the main arm, and The overstroke is designed so that an unreasonable force is not applied between the members.

As an example of such a device, during the shutter charge, the force of the setting member against the driving member is not forcibly applied to the main arm even though the main arm stops at a predetermined position. The conventional example is described in Japanese Utility Model Laid-Open No. 1-173726. According to this conventional example, the driving member for the trailing blade group is composed of two members, and these two members are used for shutter charging until the trailing blade group reaches a predetermined charge position (superposition / storage position). Operate together, but after the drive pin provided on one member and interlocking with the main arm of the trailing blade group abuts on one end of the arcuate hole formed on the ground plate, the other member Only a slight movement is made to stop. Therefore, it is not necessary for the rear blade group to perform an extra operation in the charging direction, and the storage space above the aperture can be minimized.

[0004]

However, in the structure of the conventional example as described above (generally, such a structure is referred to as an overcharge absorbing mechanism), the driving member must be composed of two members. In addition to the drive spring, a spring for cooperating the two members is required, and the number of parts is large, and the two members must be coaxially mounted. Therefore, there is also a problem that an extra space is required in the axial direction. On the other hand, in recent years, components have been made synthetic resin from the viewpoints of weight reduction and cost reduction, and the synthetic resin has already been realized for the shutter blades as well as various components. Therefore, an arm that pivotally supports a plurality of blades is expected to appear at an early stage, taking into account the structural advantages.

The present invention has been made in order to solve such problems, and an object thereof is to manufacture a main arm pivotally supporting a plurality of blades with a synthetic resin in a special shape. By doing so, it is possible to provide a focal plane shutter for a camera with a reduced number of parts, a low cost, and a space-saving overcharge absorption mechanism.

[0006]

In order to achieve the above object, the present invention forms a pair of blade groups by pivotally supporting a plurality of blades with a plurality of arms pivotally attached to a shutter base plate. ,
In a focal plane shutter for a camera in which the main arm of each blade group is reciprocally operated by the drive pin of each drive member to open and close each blade group, at least one of the blade group main arms is made of synthetic resin. A pressing portion integral with the main arm is formed in the vicinity of the pivotal portion of the main arm via an elastic portion, and the drive pin of the drive member is pressed by the pressing portion and the vicinity thereof. So that the part is on the charge operation direction side of the main arm,
The main arm contacts the stopper at the final stage of the charging operation.

Further, in the focal plane shutter for a camera of the present invention, preferably, a groove portion orthogonal to the axial direction of the drive pin is provided on the peripheral surface of the drive pin, and the pressing portion and the vicinity portion form the groove portion. Make sure to hold it. Furthermore, the focal plane shutter for a camera of the present invention is preferably
The pressing portion and the vicinity portion are formed to be thicker than other portions of the main arm.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to three illustrated embodiments. FIG. 1 is an exploded perspective view of the first embodiment, and FIG. 2 is an enlarged plan view of an essential part of FIG. FIG. 3 is a perspective explanatory view of the second embodiment, and FIG. 4 is a perspective explanatory view of the third embodiment.

First, the first embodiment shown in FIGS. 1 and 2 will be described. An intermediate plate 2 and a cover plate 3 are attached to the shutter base plate 1 at predetermined intervals, and the respective openings 1a,
By combining 2a and 3a, a substantially rectangular exposure aperture is formed. Further, shafts 1b, 1c, 1d are erected on the front surface side of the shutter base plate 1, and a front blade driving member 4 and a rear blade driving member 5 are rotatably attached to the shafts 1b, 1c, respectively, and the shaft 1d. A setting member 6 is rotatably attached to the.

The leading blade driving member 4 and the trailing blade driving member 5 are
Each has an iron piece member mounting portion 4a, 5a, and the iron piece member is adsorbed and held by a release type electromagnet at a charging position before the start of exposure traveling, and is sequentially released from the electromagnet during exposure traveling. It is designed to be rotated clockwise by a non-spring. The setting member 6 rotates clockwise in conjunction with the film winding, and pushes the leading blade driving member 4 and the trailing blade driving member 5 against the engaging portions (not shown) provided on their back surfaces, It is designed to rotate counterclockwise to the charge position. In this case, since the set member 6 pushes the engaging portion on the back surface of each driving member, a sleeve is formed at the fitting portion of each driving member with the shafts 1b and 1c downward. A spacer may be provided at the base of 1c. Further, the setting member 6 may be rotated by pushing the peripheral end surface of each drive member.

Between the shutter base plate 1 and the intermediate plate 2, 4
A front blade group 7 having a single-piece configuration is arranged, and each front blade 7a,
7b, 7c and 7d are connected to the main arm 8 and the auxiliary arm 9. For their connection, a rivet type connecting shaft 10 having a head is connected to each arm 8, 9 and each blade 7a, 7b,
The arms 8 and 9 are inserted into holes formed in 7c and 7d, and the tips thereof are caulked to the blades 7a, 7b, 7c and 7d. Therefore, although not clear in FIG. 1, the head of the connecting shaft 10 is in a state of protruding from the surfaces of the arms 8 and 9.

The main arm 8 is made of synthetic resin, and a sleeve 8a is formed at the base thereof. The sleeve 8a is rotatably fitted to a shaft 1e provided upright on the rear surface of the shutter base plate 1. doing. Also, the base of this main arm 8,
That is, in the vicinity of the position pivotally attached to the shutter base plate 1, the pressing portion 8b and the engaging portion 8c are arranged so as to face each other.
Is formed, and the base of the pressing portion 8b is an elastic portion 8d. The hole 9a of the auxiliary arm 9 is rotatably fitted to a shaft 1f provided upright on the rear surface of the shutter base plate 1. The drive pin 4b of the leading blade drive member 4 penetrates an arcuate slot 1g formed in the shutter base plate 1 and is sandwiched by the pressing portion 8b and the engaging portion 8c, and its tip is formed on the cover plate 3. It is fitted in the arc-shaped slot 3b.
Therefore, when the leading blade driving member 4 rotates in the clockwise direction, the leading blade group 7 retracts from the exposure aperture while being folded, and when it rotates in the counterclockwise direction, the leading blade group 7 is in an expanded state and closes the exposure aperture. There is.

When the leading blade group 7 is operated in this manner, a blade pressing member 11 is provided at the tip of each blade in order to close the overlap between the blades and stabilize the operation. The blade pressing member 11 and the sleeve 8a
Due to the presence of the arms 8, 9 and the leading blade group 7, the intermediate plate 2
Although the head of the connecting shaft 10 is pushed to the side so as not to contact the back surface of the shutter base plate 1, the axial dimension of the sleeve 8a cannot be made too large in order to keep the shutter as a whole thin. Then, since the arms 8 and 9 and the leading blade group 7 actually bend, the head of the connecting pin 10 that connects the arms 8 and 9 and the leading blade 7a comes into contact with the back surface of the shutter base plate 1. . Therefore, the connecting pin 10
In order to prevent the head of the head from touching, a thin relief groove (not shown) is formed on the back surface of the shutter base plate 1 in accordance with the operation locus of the head.

Between the intermediate plate 2 and the cover plate 3, there is arranged a rear blade group 12 composed of four blades, and the rear blades 12a, 1 are provided.
2b, 12c, and 12d are similar to the case of the front blade group 7, and are connected to the main arm 13 and the auxiliary arm 14 by the connecting shaft 15.
Are connected at two points. In the case of the rear blade group 12, since the front blade group 7 is arranged inside out, the head of the connecting shaft 15 projects toward the cover plate 3 side, and the caulking portion with each rear blade is shown in the drawing. It is shown. The main arm 13 is made of synthetic resin, and a sleeve 13a is formed on the base of the main arm 13 toward the cover plate 3 side.
a is rotatably fitted to a shaft 1i provided upright on the rear surface of the shutter base plate 1. A pressing portion 13b and an engaging portion 13c are formed on the base of the main arm 13 so as to face each other, and the base of the pressing portion 13b is an elastic portion 13d. The hole 14a of the auxiliary arm 14 is rotatably fitted to a shaft 1j provided upright on the rear surface of the shutter base plate 1.

The drive pin 5b of the trailing blade drive member 5 penetrates an arcuate slot 1h formed in the shutter base plate 1 and is sandwiched by a pressing portion 13b and an engaging portion 13c, and its tip is covered by the cover plate 3. It is fitted in the arcuate slot 3c formed in the. Therefore, when the trailing blade drive member 5 rotates clockwise, the trailing blade group 12 is in the unfolded state to close the exposure aperture, and when it rotates counterclockwise, the trailing blade group 12 is folded and retracts from the exposure aperture. . A blade pressing member 1 is provided at the tip position of each rear blade.
6 is provided, and the reason why the blade pressing member 16 and the sleeve 13a are present is the same as the description of the leading blade group 7 described above. It should be noted that stoppers 1m and 1n are provided upright on the rear surface of the shutter base plate 1 so that the main arms 9 and 13 abut at the charging position.
In addition, a configuration in which each drive member 4, 5 is held at the charging position,
Since the structure of the drive spring that causes each of the drive members 4 and 5 to perform the exposure travel is well known, the illustration and description thereof will be omitted.

In such a focal plane shutter, the embodiment of the present invention is the structure of the main arms 8 and 13 which come into contact with the stoppers 1m and 1n. Therefore, the configuration at this point will be described in detail with reference to FIG. FIG. 2 is a view of the shutter base plate 1 seen through, showing only a portion related to the rear blade group 12, and shows a charging state of the rear blade group 12. In order to simplify the drawing, of the four blades pivotally supported by the arms 13 and 14, only the blade 12a for slit formation is shown. As can be seen from FIG.
The elastic portion 13d biases the pressing portion 13b toward the engaging portion 13c, and the driving pin 5b of the trailing blade drive member 5 is sandwiched between the pressing portion 13b and the engaging portion 13c by the biasing force. .

As described above, when the setting member 6 rotates clockwise during shutter charging, the trailing blade drive member 5 rotates counterclockwise. The trailing blade drive member 5 charges a well-known driving spring (not shown) on the one hand by its rotation, and rotates the main arm 13 counterclockwise by the driving pin 5b on the other hand, so that the trailing blade group 12 is well-known. From the unfolded state covering the exposure aperture,
Move to the superposed state shown. During this operation, the elastic portion 13d of the main arm 13 does not deform and the pressing portion 1
The state of being sandwiched by 3b and the engaging portion 13c is maintained.

After that, when the position shown in FIG. 2 is reached, the main arm 1
3 contacts the stopper 1n. The rotation of the setting member 6 is
Since it is performed a little more, the trailing blade drive member 5 also continues to rotate slightly, the drive pin 5b deforms the elastic portion 13d and pushes the pressing portion 13b, and stops at the position indicated by the alternate long and short dash line. In the present embodiment, the force due to the overcharge operation of the trailing blade drive member 5 is absorbed in this way.
After that, when the setting member 6 returns in the counterclockwise direction, as is well known, the trailing blade drive member 5 stops in a state where it returns slightly in the clockwise direction, and the drive pin 5b and the pressing portion 13b are in the solid line state in FIG. . This position is the initial position for the exposure traveling of the rear blade group 12.

As described above, in this embodiment, when the rear blade drive member 5 is overcharged, the rear blade group 1
No. 2 does not operate in the charging direction. Therefore, there is a feature that it is not necessary to increase the vertical dimension of the space for storing the rear blade group 12. Further, in the conventional focal plane shutter, the drive pin is usually fitted into the hole of the main arm. However, in such a case, there is a fitting error and the operation of the blade group becomes unstable. Therefore, in the related art, a biasing force is applied to the main arm or the auxiliary arm by a spring or the like, which is called backlash, but according to the present embodiment, the drive pin 5b is pressed by the force of the elastic portion 13d. Since it is securely sandwiched between the portion 13b and the engaging portion 13c, it is possible to omit the conventional spring for backlashing.

In the description of FIG. 2, the relationship between the main arm 13 of the trailing blade group 12 and the stopper 1n has been described, but as can be seen from FIG. 1, the main arm 8 of the leading blade group 7 also has a different shape. However, the pressing portion 8b, the engaging portion 8c, and the elastic portion 8d which are substantially the same are formed, and the stopper 1m
With respect to the relationship with, except for the storage space, the above description can be applied as it is. Further, in the present embodiment, such a configuration is adopted for both the main arm 8 and the main arm 13, but depending on the design, it does not prevent adoption for only one of them. .

Next, the second embodiment shown in FIG. 3 will be described. The main arm 23 of the trailing blade group shown in FIG. 3 (of course, may be the main arm of the leading blade group) is made of synthetic resin, and the pressing portion 23b is provided near the position pivotally attached to the shutter base plate. , Has an engaging portion 23c and an elastic portion 23d, and is substantially the same as the main arm 13 of the first embodiment. The different points are that a sleeve is not formed in the rotating portion and the blade group pivotally supports three blades, which are not directly related to the present invention. Rear blade drive member 2
5, the iron piece member mounting portion is not shown in the drawing, and a circumferential groove 25b-1 is formed in the drive pin 25b thereof, and the pressing portion 23b and the engaging portion 23c are formed in the groove 2
The drive pin 25b is sandwiched in 5b-1.

With this structure, the present embodiment has the effect of maintaining the posture of the main arm 23 during exposure traveling and suppressing irregular movement (movement / bending) in the direction perpendicular to the plane. However, the possibility of collision with the intermediate plate or the cover plate is reduced, which helps stabilize the exposure running of the rear blade group. Therefore, the sleeve described in the first embodiment is not always necessary. The other features are the same as in the first embodiment, and the same applies to the present embodiment. In the present embodiment, the drive pin 25
Although b has a cylindrical shape as a whole, and the groove 25b-1 is formed over the entire circumference of its circumferential surface, the drive pin 2
5b need not be limited to a cylindrical shape, and the groove 25b
-1 is also the pressing portion 23b and the engaging portion 23c in accordance with the above-mentioned purpose.
It does not need to be formed over the entire circumference as long as it is sandwiched between and and can operate smoothly.

Finally, the third embodiment shown in FIG. 4 will be described. The main arm 33 of the trailing blade group shown in FIG. 4 is made of a synthetic resin, a sleeve 33a is formed at the pivotal portion, and the vicinity of the pivotal portion is thicker than the pivotal supporting portion of the blade. And the pressing portion 33b, the engaging portion 33c, the elastic portion 33d.
Are formed. Also in the case of this embodiment, the number of blades pivotally supported is three. The function of the main arm 33 is the same as that of each main arm described in the first and second embodiments,
With the configuration as in this example, strength and durability are further improved. It is needless to say that the main arm 33 may be used as the main arm of the front blade group, and can correspond to any of the driving members shown in the first and second embodiments.

[0024]

As described above, according to the present invention, the main arm that pivotally supports a plurality of blades is made of a synthetic resin in a special shape, so that the overcharge operation of the driving member can be absorbed. A costly focal plane shutter for a camera can be obtained. Further, according to the present invention, the conventionally known rattling countermeasure for coping with the fitting error between the drive member and the main arm is eliminated.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a first embodiment of the present invention.

FIG. 2 is an enlarged plan view of a main part of FIG.

FIG. 3 is a perspective explanatory view of a second embodiment of the present invention.

FIG. 4 is a perspective explanatory view of a third embodiment of the present invention.

[Description of Reference Signs] 1 shutter base plate 1b, 1c, 1d, 1e, 1f, 1i, 1j axis 1g, 1h, 3b, 3c slot 1m, 1n stopper 2 intermediate plate 3 cover plate 4 leading blade drive member 4a, 5a iron piece member Mounting parts 4b, 5b, 25b Drive pins 5, 25 Rear blade drive member 6 Set member 7 Leading blade group 7a, 7b, 7c, 7d Leading blade 8, 13, 23, 33 Main arm 8a, 13a, 33a Sleeve 8b, 13b , 23b, 33b Pressing part 8c, 13c, 23c, 33c Engagement part 8d, 13d, 23d, 33d Elastic part 9,14 Auxiliary arm 9a, 14a Hole 10,15 Connecting shaft 11,16 Blade pressing member 12 Rear blade group 12a , 12b, 12c, 12d Rear blade 25b-1 groove

Claims (3)

[Claims] 1. A plurality of blades are pivotally supported by a plurality of arms pivotally attached to a shutter base plate to form two sets of blade groups, and a main arm of each blade group is reciprocated by drive pins of respective drive members. In a focal plane shutter for a camera, which is operated to open and close each blade group, at least one of the blade group main arms is made of synthetic resin,
A pressing part integral with the main arm is formed in the vicinity of the pivotal part of the main arm via an elastic part, and a drive pin of the drive member is formed between the pressing part and the vicinity. The focal plane shutter for a camera, characterized in that the main arm is held so as to be on the charge operation direction side of the main arm, and the main arm contacts the stopper at the final stage of the charge operation. 2. A groove portion orthogonal to an axial direction of the drive pin is provided on a peripheral surface of the drive pin, and the pressing portion and the vicinity portion sandwich the groove portion.
The focal-plane shutter for the camera described in. 3. The focal plane shutter for a camera according to claim 1, wherein the pressing portion and the vicinity portion are formed to be thicker than other portions of the main arm.