JP3593424B2 - Focal plane shutter - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focal plane shutter for a camera in which a leading blade group and a trailing blade group are sequentially moved in the same direction during photographing, and a film is exposed by slits formed by the leading and trailing blade groups.
[0002]
[Prior art]
As single-lens reflex cameras have become smaller and more sophisticated, there has been a demand for a focal plane shutter of this type to be smaller and faster. As is well known, the focal plane shutter is disposed immediately before the film surface. Therefore, in order to reduce the size, the storage space for the blades in the superimposed state (the state retracted from the exposure opening) is reduced. It is effective to do so. However, for that purpose, it is necessary to increase the number of blades in each blade group. When the number of blades is increased, the number of overlapping surfaces of the blades in the developed state (covering the exposure opening) increases, so that the weight of the entire blade increases. Therefore, there is a problem that the blades must be reduced in weight in order to obtain the conventional maximum speed by the conventional driving force.
[0003]
On the other hand, in order to increase the speed, it is necessary to increase the driving force or reduce the weight of the blade. However, increasing the driving force more than ever is extremely difficult from the viewpoint that stable performance must be obtained. Therefore, it is important to reduce the weight of the blades in order to cope with higher speeds. By the way, reducing the weight of the blade means that the plane area or the thickness of each blade must be reduced if the material surface is not considered. However, when the plane area of each blade is reduced, the overlapping area of the blades in the unfolded state is reduced, and light leakage to the film surface when the camera is not used becomes a problem. On the other hand, if the thickness of each blade is too small, the blade is largely bent by vibration or impact when the camera is carried, and harmful light leakage is also performed.
[0004]
As described above, in order to reduce the size and speed of the shutter, it is necessary to take measures against light leakage when the camera is not used. For this reason, various precautions have been taken in the production, including the technology of surface treatment. However, as a method that can solve the problem structurally, for example, one described in Japanese Patent Application Laid-Open No. 54-151439 is known. Have been. In this conventional example, when the shutter is set in conjunction with the film winding after the photographing is completed, the front blade group operates to the set position together with the driving member for the front blade, but the rear blade group immediately moves to the set position. Does not operate, and only the rear blade drive member operates to the set position. Then, when the next photographing is performed, the rear wing group is moved to the set position in an initial stage of the release. Therefore, when the camera is not used, the exposure opening is always covered by the front blade group and the rear blade group, and light leakage can be prevented. The present invention relates to a focal plane shutter having such a double light blocking function.
[0005]
[Problems to be solved by the invention]
By the way, as described in the above-mentioned publication, a conventional focal plane shutter having a double light blocking function is configured such that a normal rear blade driving member is composed of two members with a spring interposed therebetween. And they were arranged on the same axis. Therefore, there are problems that the number of components increases, the mounting configuration thereof becomes complicated, the arrangement of other members is greatly affected, and the installation volume of the entire opening / closing control mechanism unit increases.
The present invention has been made to solve such a problem, and an object of the present invention is to provide a camera having a double light-shielding function that can be manufactured in a compact form with a smaller number of parts than before. To provide a focal plane shutter.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a focal plane shutter for a camera according to the present invention pivotally supports a plurality of blades by a shutter base plate having an exposure opening and at least two arms each including a main arm. A front blade group and a rear blade group for opening and closing the exposure opening by reciprocating rotation of each main arm; a deterrent means provided in the rear blade group; A set spring biasing in the opening direction, a driving member for the front blade having an operation pin connected to the main arm of the front blade group, and being driven by the driving spring for the front blade during the exposure operation. A driving member for the rear blade, which has an operating pin capable of contacting a main arm of the rear blade group, and which is rotated by the rear blade driving spring against the urging force of the set spring during an exposure operation; As a deterrent It has an operating part in addition to a deterrent part that can be touched and operates from an initial position at the time of setting to operate each of the drive members to the set position, and at the time of release, is returned to the initial position prior to the exposure operation of each of the drive members. A member provided with the setting member, a locking portion provided on the shutter base plate and locking the suppressed means at the exposure operation end position, and an operated portion which is pushed by the operation portion to release the locking when set. Stopping means, wherein when the locking is released, the operation by the set spring is suppressed by the suppressing part, and when the set member returns to the initial position, the restraint is released. It is configured as follows.
[0007]
In the focal plane shutter according to the present invention, preferably, the suppressed means is provided on a main arm of the rear blade group.
In the focal plane shutter according to the present invention, preferably, the main arm of the front blade group and the driving member for the front blade are integrally formed of synthetic resin.
In the focal plane shutter according to the present invention, preferably, the locking means and the shutter base plate are integrally formed of synthetic resin, and the locking means is provided with flexibility. I do.
Further, in the focal plane shutter according to the present invention, preferably, the locking means has a slope portion which is engaged with the suppressed means at the time of exposure operation and is pressed against an elastic return force. I do.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to an embodiment shown in FIGS. FIG. 1 is a plan view showing a state immediately after the end of the exposure operation. 2 to 5 are plan views sequentially showing a process of setting the driving member for the front blade and the driving member for the rear blade from the state of FIG. 1, and FIG. 6 shows a completed state of the setting of each driving member. It is a top view. FIG. 7 is a plan view showing a state in which the set member returns to the initial position and the rear blade group reaches the set position prior to the exposure operation of each drive member at the time of release. FIG. 8 is a sectional view conceptually showing the configuration of the main part.
[0009]
First, the configuration of the present embodiment will be described. The shutter base plate 1 is made of a synthetic resin and has an opening 1a for exposure at a substantially central portion, but only the left half thereof is shown in the drawing. As is well known, an intermediate plate and a cover plate (not shown) are sequentially attached to the rear side of the shutter base plate 1 at predetermined intervals. An opening having a shape similar to that of the opening 1a is also formed in the intermediate plate and the cover plate, and an exposure opening as a shutter unit is determined by combining these three openings. In the case of this embodiment, a front blade group is arranged between the shutter base plate 1 and the intermediate plate, and a rear blade group is arranged between the intermediate plate and the cover plate.
[0010]
On the front side of the shutter base plate 1, shafts 1b, 1c, and 1d are erected, and the shafts 1b and 1c also protrude toward the rear side of the shutter base plate 1. On the back side of the shutter base plate 1, shafts 1e and 1f are erected. Further, the shutter base plate 1 is formed with arc-shaped holes 1g, 1h, 1i, and 1j, of which a buffer member 2 made of butyl rubber is attached to the lower end of the hole 1g as is well known. I have. At the lower end of the hole 1j, a locking means 1k formed integrally with the shutter base plate 1 is provided. The locking means 1k is not flexible, locking surface 1k 1 at its _tip, is the slope 1k ₂ is formed, is erected on the surface side of the shutter base plate 1 and in cross section have a semicircular the pin 1k ₃ has been.
[0011]
The rear blade group in the present embodiment is disposed on the back side of the shutter base plate 1 as described above, and includes a main arm 3, a sub arm 4, and four blades 5, which are pivotally supported by them in a known manner. 6, 7, and 8. The main arm 3 is pivotally connected to the shaft 1c, and the sub arm 4 is pivotally connected to the shaft 1f. The main arm 3 has a pin 3a erected and a notch 3b formed therein, and is urged counterclockwise by a set spring 9. Pin 3a is projected on the surface side of the shutter base plate 1 through the hole 1j, by pressing and sliding contact with the inclined surface 1k ₂ locking means 1k mentioned above, it is possible to deflect the locking means 1k It has become. Moreover, this pin 3a, as can be seen from the two Fig. 1, the engaging portion 3a _1, taken over a period of about 90 degrees is formed, adapted to engage the locking surface 1k ₁ locking means 1k mentioned above It has become.
[0012]
Although the configuration of the front blade group in the present embodiment is a well-known configuration itself, it is not shown in the drawings. However, the outline thereof will be briefly described. The main arm is pivotally connected to the shaft 1b, and the sub-arm is the shaft shaft 1e. Is pivoted to. And four wings are pivotally supported on them. However, the main arm is not provided with any of the above-described pins 3a and notches 3b, and is not biased by a spring corresponding to the set spring 9 described above. However, as an alternative to the above-mentioned cutout 3b, a hole is formed to be fitted to an operating pin of a driving member for a front blade described later.
[0013]
On the front side of the shutter base plate 1, a front blade drive member 10 and a rear blade drive member 11 made of synthetic resin are rotatably mounted on the shafts 1b and 1c, respectively, and a front blade drive spring 12 and a rear blade drive member, respectively. Is biased clockwise by the driving spring 13. These driving members 10 and 11 are provided with operating pins 10a and 11a, respectively. The operating pins 10a pass through the arc-shaped holes 1g and are formed in the main arms of the above-mentioned front blade group. The operating pin 11a can penetrate the arc-shaped hole 1h and come into contact with the notch 3b formed in the main arm 3 of the rear blade group. Therefore, the main arm of the front blade group reciprocates in conjunction with the rotation of the front blade drive member 10, but the main arm 3 of the rear blade group rotates the rear blade drive member 11 clockwise. In this case, they are interlocked, but when they are turned counterclockwise, they are not interlocked.
[0014]
Further, the front blade driving member 10 and the rear blade driving member 11 are formed with mounting portions 10b, 11b, respectively, and iron piece members 14, 15 are mounted thereon, respectively. The specific configuration of the iron piece members 14 and 15 and the mounting configuration thereof are clearly shown in FIG. As shown in cross section in FIG. 3, the iron pieces 14 and 15 are composed of iron pieces 14a and 15a to be attracted to an electromagnet and shafts which are loosely fitted into holes formed in the mounting parts 10b and 11b. 14b, 15b and flanges 14c, 15c, which can also move in the axial direction of the shafts 14b, 15b. The compression springs 16 and 17 are interposed between the iron pieces 14a and 15a and the mounting portions 10b and 11b, and bias the flanges 14c and 15c to contact the mounting portions 10b and 11b. are doing. Further, the front blade drive member 10 is provided with a roller 10c as a pushed portion, and the rear blade drive member 11 is also formed with a cam surface 11a as a pushed portion.
[0015]
A set member 18 made of a synthetic resin is rotatably attached to the shaft 1 d of the shutter base plate 1, and is urged counterclockwise by a spring 19. The set member 18 is formed with a notch 18a that engages with a not-shown interlocking member, and is turned clockwise against the spring 19 by the interlocking member during setting. ing. On the back side of the set member 18, a projection 18b fitted into the arc-shaped hole 1i is formed to regulate the rotation angle of the set member 18. Further, the set member 18 is formed with two cam-shaped pushing portions 18c and 18d, and the pushing portion 18c is provided on the roller 10c of the leading blade driving member 10, and the pushing portion 18d is provided on the rear blade driving member. The cam surface 11c of the member 11 can be engaged with the cam surface 11c.
[0016]
Two cam surfaces 18e and 18f are further formed on the back side of the set member 18. The two cam surfaces 18e, 18f, as seen from the schematic diagram of FIG. 8, are formed in two stages toward the shutter base plate 1, the cam surface 18e is in contact with the engagement pin 1k ₃ locking means 1k The cam surface 18f can be engaged with the pin 3a of the main arm 3. On the other hand, although not shown because it is well known, an attachment plate (sometimes referred to as an upper base plate) is attached to the front surface side of the shutter base plate 1 so as to be parallel to the shutter base plate 1. An electromagnet for the front blade and an electromagnet for the rear blade are attached to the lower surface, that is, the surface on the shutter base plate 1 side. Therefore, the iron core member 20 of the electromagnet for the front blade and the iron core member 21 of the electromagnet for the rear blade are shown by dashed lines in each drawing.
[0017]
Next, the operation of the present embodiment will be described. FIG. 1 shows a state immediately after the end of shooting. Therefore, in this state, the set member 18 is rotated counterclockwise by the spring 19, and is at the rest position where the protrusion 18b contacts the lower end edge of the hole 1i, that is, the initial position. The driving member 10 for the front blade and the driving member 11 for the rear blade are in a state where the exposure operation is completed by the driving springs 12 and 13, and the front blade group (not shown) overlaps four blades. The rear blade group covers the exposure opening 1a by developing the four blades 5, 6, 7, and 8 in a position below the exposure opening 1a.
[0018]
In this state, when the not-shown interlocking member pushes the notch 18a in conjunction with the film winding, the set member 18 rotates clockwise against the spring 19. By this rotation, first, the pushing member 18c of the setting member 18 pushes the roller 10c which is the pushed member. Therefore, the leading blade driving member 10 rotates in the counterclockwise direction, and the main arm of the leading blade group (not shown) is rotated in the counterclockwise direction on the shaft 1b by the operating pin 10a. As a result, the four blades (not shown) start operating upward while being deployed, and when the slit forming blades reach the substantially lower edge position of the exposure opening 1a, the other pushing portion of the set member 18 is moved. 18d engages with the cam surface 11c which is the pushed portion. This state is shown in FIG.
[0019]
When the setting member 18 rotates clockwise from the state of FIG. 2, the cam surface 11 c, which is the pushed portion, is pushed by the pushing portion 18 d, and the rear blade drive member 11 is pressed against the drive spring 13. Rotated counterclockwise. Engaged this time, tries to follow the operating pin 11a main arm 3 of the rear blade group also by the biasing force of the set spring 9, the engaging portion 3a ₁ of the pin 3a is the locking surface 1k ₁ locking means 1k Because they are stopped, they cannot follow. Therefore, the rear blade group does not operate, and the state where the opening for exposure 1a is covered by the four blades 5, 6, 7, 8 is maintained. In this manner, when the set member 18 rotates a predetermined angle while operating only the front blade group by the front blade drive member 10, as shown in FIG. 3, the cam surface 18e of the set member 18 in contact with the pin 1k ₃ of 1k. On the other hand, in this state, the iron piece portions 14a and 15a of the iron piece members 14 and 15 are not completely in contact with the iron core members 20 and 21.
[0020]
Setting member 18, the still continues to rotate, the cam surface 18e is press pin 1k _3, to deflect the locking means 1k, it begins to release the locking for the pin 3a of the main arm 3. This state is shown in FIG. At this time, the iron piece portion 14a of the iron piece member 14 contacts the iron core member 20, but the iron piece portion 15a of the iron piece member 15 has not yet completely contacted the iron core member 21. Immediately thereafter, the locking of the main arm 3 to the pin 3a is released. However, the pin 3a immediately comes into contact with the cam surface 18f, and its operation is suppressed. Therefore, the rear blade group is only slightly operated by the set spring 9 and still covers the exposure opening 1a by the four blades 5, 6, 7, and 8. This state is shown in FIG. In this state, the iron piece portion 14a of the iron piece member 14 is in close contact with the suction surface of the iron core member 20 by slightly tensioning the compression spring 16, and the iron piece portion 15a of the iron piece member 15 is Is almost in contact with.
[0021]
When the set member 18 is further rotated, the leading blade driving member 10 rotates with the compression spring 16 being further tightened, and the leading blade group is completely expanded to cover the exposure opening 1a. The rear blade drive member 11 brings the iron piece 15 a of the iron piece member 15 into close contact with the suction surface of the iron core member 21 by the tension of the compression spring 17. The set state obtained in this way is shown in FIG. In this state, the projection 18b of the set member 18 is in contact with the upper end edge of the arc-shaped hole 1i, and the iron pieces 14a, 15a of the iron pieces 14, 15 are compressed by the compression springs 16, 17, so that the iron core members 20, 21 are formed. And the flanges 14c, 15c and the mounting portions 10b, 11b are in a non-contact state. Both the front blade group and the rear blade group are in the developed state, and both of them shield the exposure opening 1a from light. Accordingly, light leakage in this state is completely prevented. Then, the setting member 18 holds such a state until the next photographing.
[0022]
Next, the shutter release operation will be described. When the release button is pressed, the power switch is closed in the initial stage, the photometric circuit operates, and both coils of the electromagnet for the front blade and the electromagnet for the rear blade are energized, and the iron core members 20 and 21 are excited. Therefore, the iron piece portions 14a, 15a of the iron piece members 14, 15 are magnetically attracted to the iron core members 20, 21. Immediately thereafter, the holding force is released, and the spring 19 starts the operation of returning to the initial position. In the initial stage of the return operation, the set member 18 returns to a position where the set member 18 is slightly rotated counterclockwise from the position shown in FIG. 5, and the engagement between the cam surface 18f of the set member 18 and the pin 3a of the main arm 3 is released. Then, the main arm 3 rotates counterclockwise about the shaft 1c by the urging force of the set spring 9. Therefore, the four blades 5, 6, 7, and 8 of the rear blade group operate upward, and are superimposed and stored at a position above the exposure opening 1a. FIG. 7 shows a state in which the set member 18 has returned to the initial position before or after that.
[0023]
Thereafter, when the energization of the coil of the electromagnet for the leading blade is cut off, the driving member 10 for the leading blade rotates clockwise at a stage where the force of the driving spring 12 for the leading blade exceeds the attraction force of the iron core member 20. Then, the front blade group is operated by the operation pin 10a, and four blades (not shown) are operated downward. By this operation, the blades are superimposed, and immediately after the opening of the exposure opening 1a is completed, the operating pin 10a of the driving member 10 for the front blade collides with the buffer member 2, and the impact force is absorbed to stop. . Therefore, the front blade group does not bounce and temporarily covers a part of the exposure opening 1a again, and is stored at a position below the exposure opening 1a.
[0024]
After the power supply to the coil of the front blade electromagnet is cut off, the power supply to the coil of the rear blade electromagnet is cut off after a predetermined time based on the measurement result by the photometric circuit. Therefore, the biasing force of the rear blade drive spring 13 causes the rear blade drive member 11 to rotate clockwise. At this time, since the force of the rear blade drive spring 13 is larger than the force of the set spring 9, the operating pin 11a of the rear blade drive member 11 pushes the notch 3b, and the main arm 3 is operated clockwise by the shaft 1c. Let it. As a result, the four blades 5, 6, 7, and 8 of the rear blade group are developed and cover the exposure opening 1a.
[0025]
The slit forming blade 5 of the rear blade group is a stage to be completely closed for exposure opening 1a, the pin 3a of the main arm 3, FLEXIBLE locking means 1k sliding contact and thereby the slope 1k ₂ locking means 1k It will work in a sluggish manner. Therefore, the operation of the rear blade group is braked. When the slit forming blades 5 have finished closing the exposure opening 1a in this way, the pressing of the locking means 1k by the pin 3a is released, and the locking means 1k returns to its original shape by its own elastic force. Then, the state shown in FIG. 1 is obtained. Therefore, the pin 3a of the main arm 3 is also collides with the lower edge of the hole 1j, the engaging portion 3a ₁ of the pin 3a is locked to the locking surface 1k ₁ locking means 1k, not bound. Therefore, it is not necessary to provide the buffer member 2 in the rear blade group as in the front blade group.
[0026]
In the above-described embodiment, the locking means 1k is formed integrally with the shutter base plate 1. However, the present invention prevents manufacture of this as a separate member and attachment to the shutter base plate 1. Absent. Further, in the above embodiment, the means for inhibiting the rear blade group, which is inhibited by the cam surface 18f of the set member 18, is provided as the pin 3a of the main arm 3, but other components such as the sub arm 4 are provided. It does not preclude providing the component. Further, in the above-described embodiment, the case where the main arm of the front blade group and the driving member 10 for the front blade are formed as separate members has been described. However, recently, the driving member and the main arm are integrally formed of synthetic resin. Techniques for forming the target have been proposed and developed. Therefore, in the leading blade system, the present invention can also be applied to the one in which the driving member and the main arm are integrally formed of synthetic resin.
[0027]
As is well known, shutters that control the start of the exposure operation of each driving member by an electromagnet include a so-called locking type and a so-called direct type. The embodiment belongs to the latter type of shutter. However, as long as the setting member (also called the charging member) is returned to the initial position at the initial stage by a release signal, a so-called locking type shutter is used. The present invention can be applied to a shutter.
[0028]
【The invention's effect】
As described above, the present invention provides a focal plane shutter in which the opening for exposure is double-shielded by the front blade group and the rear blade group immediately after shooting until the next shooting is performed. Has an extremely excellent effect that the structure is very simple and has a function of braking the operation of the rear blade group and preventing bouncing.
[Brief description of the drawings]
FIG. 1 is a plan view of an embodiment of the present invention, showing a state immediately after an exposure operation is completed.
FIG. 2 is a plan view of the embodiment of the present invention, showing a state immediately after a setting operation of a driving member for a front blade and a driving member for a rear blade is started from the state of FIG. 1;
FIG. 3 is a plan view of the embodiment of the present invention, showing a state before the set member starts releasing the locking of the rear blade group.
FIG. 4 is a plan view of the embodiment of the present invention, showing a state in which the set member has unlocked the rear blade group.
FIG. 5 is a plan view of the embodiment of the present invention, showing a state where the set member has released the locking of the rear blade group.
FIG. 6 is a plan view of the embodiment of the present invention, showing a completed state of a setting operation of each driving member.
FIG. 7 is a plan view of the embodiment of the present invention, showing a state where a set member returns to an initial position and a rear blade group reaches a set position prior to an exposure operation of each drive member at the time of release. ing.
FIG. 8 is a sectional view conceptually showing a configuration of a main part of the embodiment of the present invention.
[Explanation of symbols]
1 shutter base plate 1a exposure opening portion 1b, 1c, 1d, 1e, 1f axis 1g, 1h, 1i, 1j hole 1k locking means 1k ₁ locking surface 1k ₂ slopes _1k 3, 3a pin 2 buffer member 3 main arm 3a ₁ engagement portion 3b, 18a notch 4 sub arm 5, 6, 7, 8 blade 9 set spring 10 front blade drive member 10a, 11a operating pin 10b, 11b mounting portion 10c roller 11 rear blade drive member 11c, 18e , 18f Cam surface 12 Front blade drive spring 13 Rear blade drive spring 14, 15 Iron piece members 14a, 15a Iron piece portions 14b, 15b Shaft portions 14c, 15c Collar portion 16, 17 Compression spring 18 Set member 18b Projection portions 18c, 18d Pushing part 19 Spring 20, 21 Iron core member

Claims (5)

A shutter base plate having an opening for exposure, and a front blade for pivotally supporting a plurality of blades by at least two arms each including a main arm, and opening and closing the opening for exposure by reciprocating rotation of each main arm. A group and a rear blade group, a suppressed means provided in the rear blade group, a set spring for urging the rear blade group in a direction to open the exposure opening, and a main arm of the front blade group A driving pin for driving the front blade, which is rotated by the driving spring for the front blade at the time of the exposure operation, and an operation pin capable of contacting the main arm of the rear blade group. In operation, it has a rear blade drive member that is turned by the rear blade drive spring against the urging force of the set spring, a depressing portion that can be engaged with the suppressed means, and an operating portion. Operate from the position The member is operated to the set position, and at the time of release, the set member is returned to the initial position prior to the exposure operation of each of the driving members, and the restrained means provided on the shutter base plate and locked at the exposure operation end position. Locking means having a locking part and an operated part which is pushed by the operation part at the time of setting to release the locking, wherein the controlled means is provided when the locking is released. A focal plane shutter, wherein the operation by a spring is suppressed by the restraining portion, and the restraint is released when the set member returns to the initial position. 2. The focal plane shutter according to claim 1, wherein said inhibited means is provided on a main arm of said rear blade group. 3. The focal plane shutter according to claim 1, wherein the main arm of the front blade group and the driving member for the front blade are integrally formed of synthetic resin. 4. A focal as claimed in claim 1, wherein said locking means and said shutter base plate are integrally formed of synthetic resin, and said locking means is provided with flexibility. Plane shutter. The focal point according to any one of claims 1 to 4, wherein the locking means has a slope which is engaged with the suppressed means at the time of an exposure operation and is pressed against an elastic return force. Plane shutter.

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