JP2574020Y2 - 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, and more particularly, to a structure for engaging a blade with a driving member for moving the blade.

[0002]

2. Description of the Related Art In a focal plane shutter, when an extremely high shutter speed is to be obtained, in principle, the running speed of the blade at the time of exposure is further increased and the slit width (the leading edge at the time of exposure) is increased. The distance between the exposed blades of the blades and the exposed blades of the rear blade) is reduced as much as possible. The control of the slit width is performed by electrically controlling the timing of the start of the trailing blade after the start of the leading blade travel, but as the slit width is set to be narrower, the exact reproducibility becomes more difficult. Therefore, accurate shutter time cannot be expected. In particular, 1 /
If the realization of a high-speed shutter time of 4000 seconds or more is performed by narrowing the slit width, this effect cannot be ignored and becomes a serious problem. Therefore, in pursuing a further increase in shutter speed, it is important to increase the running speed of the blade and make the slit width as wide as possible, thereby obtaining a stable shutter time with accurate reproducibility. Exposure accuracy is increased. Further, it is more advantageous to increase the running speed of the blade from the viewpoint of increasing the strobe tuning speed so that the strobe can be used at a higher shutter speed.

[0003]

In such a shutter, when the blades are shifted from the running state to the stop state, the blades try to continue running due to inertia, while the driving member applies a braking force to the stop. Because it is about to stop, opposing forces will act. In the high-speed traveling type shutter, the traveling speed is increased by further increasing the urging force on the blades, and the traveling speed is stopped. Therefore, a larger load is applied to the engaging portion between the driving member and the blades. The portion to which this load is applied intensively is the portion where the drive lever and the blade arm are in contact with each other, and conventionally, the linking portion that is provided on the drive lever and engages with the groove of the blade arm is a cylinder. Shapes and shafts were used, and the contact was point contact, so they were prone to deformation and destruction. Further, conventionally, since a cylindrical or shaft-shaped linking portion is fixed by caulking or the like, a corresponding process is required.

The present invention has been made in view of the above-mentioned problems, and has as its object the purpose of making it extremely easy to manufacture without complicating or enlarging it. An object of the present invention is to provide a long-life focal plane shutter which is free from deformation or destruction of a blade arm or a link portion due to concentration of force due to contact and can be used for an ultra-high-speed shutter.

[0005]

In order to achieve the above object, a focal plane shutter according to the present invention comprises a shutter base plate having an opening, a blade group including a plurality of divided blades, and a swinging base plate. A blade arm movably mounted on the shaft and connected to the blade group; a blade arm rotatably mounted on the shutter base plate coaxially with the blade arm via the blade group and the blade arm; A drive lever that is moved between an unfolded state and a superposed state at the opening and is pressed from a metal plate, and the blade arm is formed with a long groove having a straight portion facing in parallel with the blade arm. The drive lever is formed by integrally bending a linking portion that makes surface contact with the inner peripheral surface of the long groove at the linear portion.

[0006]

According to the above construction, the portion where the linking portion of the drive lever comes into contact with the long groove of the blade arm has a surface contact corresponding to the thickness of the blade arm member. Are distributed over the range of the size. In other words, the impact force per unit area during one stop is smaller than that of the conventional point contact configuration.
It becomes much smaller, which leads to a dramatic improvement in durability. Further, by forming as in claim 2, its manufacture becomes extremely easy.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 shows a front blade group 1 and a rear blade group 2 of a focal plane shutter according to an embodiment of the present invention, and blade arms 3 and 4 for running the respective blade groups.
FIG. 3 is a plan view showing an initial state of the blade arms 5 and 6, and an opening 7a formed in the shutter base plate 7 is shielded by the front blade group 1 in the initial state.

The blade arms 3 and 4 are pivotally attached to the shutter base plate 7 by rotating shafts 8 and 9. Front blade group 1
Is composed of divided blades 1a, 1b, 1c, 1d,
The blades 3 are rotatably caulked to the blade arm 3 by a, 3b, 3c, and 3d, and are rotatably caulked to the blade arm 4 by the shafts 4a, 4b, 4c, and 4d. A linking portion 10a formed in a drive lever 10 described later penetrates a slot 7b formed in the shutter base plate 7 and engages with a long groove 3e of the blade arm 3. When the linking portion 10a runs along the slot 7b, the blade arm 3 rotates clockwise about the rotation axis 8 and the blade arm 4 interlocked with the rotation rotates clockwise about the rotation axis 9, so that the divided blades 1a, 1b,
The front blade group 1 constituted by 1c and 1d travels downward to open the opening 7a.

The blade arms 5 and 6 are pivotally attached to the shutter base plate 7 by rotating shafts 11 and 12. The rear blade group 2 is composed of divided blades 2a, 2b, 2c, 2d,
The blades 5 are rotatably caulked to the blade arm 5 by shafts 5a, 5b, 5c, and 5d.
The blade arm 6 is rotatably caulked by a, 6b, 6c and 6d. A linking portion 13a formed on a drive lever 13 described later penetrates a slot 7c formed on the shutter base plate 7 and engages with a long groove 5e of the blade arm 5. When the linking portion 13a runs along the slot 7c, the blade arm 5 rotates clockwise about the rotation shaft 11, and the blade arm 6 interlocked with the rotation rotates clockwise about the rotation shaft 12, so that the divided blades 2a, The rear blade group 2 constituted by 2b, 2c, and 2d travels downward to shield the opening 7a.

FIG. 2 is a plan view showing an initial state of a driving lever 10 for moving the front blade group 1 and a driving lever 13 for moving the rear blade group 2 of the focal plane shutter according to an embodiment of the present invention. The drive levers 10 and 13 are obtained by bending a metal plate by press working. FIG. 3 is a perspective view of the drive lever 10 of the focal plane shutter according to the embodiment of the present invention.

A drive lever 10 for driving the front blade group 1
Is pivotally mounted on the shutter base plate 7 by a drive shaft 14 coaxial with the rotation shaft 8 and is urged clockwise by a spring 15, but is disposed on the drive lever 10. Since the iron piece 16 is attracted by an electromagnet (not shown), the initial state is maintained. Therefore, the leading blade group 1 connected to the blade arm 3 engaged with the linking portion 10a formed on the drive lever 10 also maintains the initial state, that is, the deployed state. Similarly, the drive lever 13 for running the rear blade group 2 is provided with the drive shaft 1 coaxial with the rotation shaft 11.
7, is pivotally attached to the shutter base plate 7 in a swingable manner, and is urged in the clockwise direction by a spring 18. However, an iron piece 19 provided on the drive lever 13 is attracted by an electromagnet (not shown). So the initial state is maintained. Therefore, the link 1 formed on the drive lever 13
The rear blade group 2 connected to the blade arm 5 engaged with 3a also maintains the initial state, that is, the superposed state.

Thereafter, at the time of exposure, the attraction of the electromagnet of the iron piece 16 is released first, and the driving lever 10 rotates and rotates by the urging of the spring 15, and after a set time, the attraction of the electromagnet of the iron piece 19 is released and the drive is started. The lever 13 rotates and travels by the bias of the spring 18. Then, at a predetermined position, a stop braking action is applied to the drive lever in various ways.

In the present invention, the link portions 10a, 13a
Are formed by bending the drive levers 10 and 13, and the cross-sectional shape thereof is a rectangle parallel to the parallel straight portions of the long grooves 3e and 5e. Surface contact. Therefore, at the time of a stop, the linking portions 10a and 13a decelerate rapidly by the stop braking action, while the blade arms 3 and 5 maintain the speed by inertia and collide with the linking portions 10a and 13a in the long grooves 3e and 5e. However, the impact force due to the collision is dispersed in an area corresponding to the thickness of the members of the blade arms 3 and 5, and the impact is reduced.

[0014]

As described above, in the focal plane shutter according to the present invention, since the surface contact corresponds to the thickness of the blade arm member, the impact force of the collision at the time of stoppage is large due to the contact area. Will be scattered over the range. That is, the impact force per unit area at one stop is significantly smaller than that of the conventional point contact or line contact configuration.

Therefore, the wear damage does not proceed locally as in the prior art, and the average wear is very moderate over a wide area, so that the initial state of the members is maintained for a long period of time, and the running characteristics of the shutter blades are also reduced. The initial state can be secured over a long period. In addition, since the average wear is extremely slow over a large area, the wear is not suddenly disabled due to the progress of local wear as in the past, and the user can perceive it as a very slow change over time. Also, the sense of use is more reliable.

Further, according to the present invention, the relationship between the linking portion of the drive lever and the long groove of the blade arm is determined even if there is a folding position error of the linking portion from the drive shaft or a dimensional accuracy error of the linking portion. Is absorbed as the movement of the link in the long groove, and these errors do not significantly change the movement of the blade arm, so the required processing accuracy is not severe, the structure is simple and practical And a focal plane shutter excellent in image quality.

[Brief description of the drawings]

FIG. 1 is a plan view showing an initial state of a shutter blade of a focal plane shutter according to an embodiment of the present invention.

FIG. 2 is a plan view showing an initial state of a driving lever for moving a shutter blade of the focal plane shutter according to the embodiment of the present invention;

FIG. 3 is a perspective view of a drive lever for moving a leading blade of the focal plane shutter according to the embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Front blade 2 Rear blade 3,4,5,6 Blade arm 7 Shutter base plate 8,9,11,12 Rotating shaft 10a, 13a Coupling unit 10,13 Drive lever 14,17 Drive shaft 15,18 Spring 16,19 Iron piece

Claims (2)

(57) [Scope of request for utility model registration] A shutter base plate having an opening, a blade group including a plurality of divided blades, a blade arm pivotally mounted on the shutter base plate and connected to the blade group; A shutter base plate is pivotally mounted on the shutter base plate so as to be coaxial with the blade arm so as to swing freely. The shutter base plate is moved through the blade group and the blade arm between the unfolded state and the superimposed state at the opening and pressed from a metal plate. A drive lever to be machined, the blade arm is formed with a long groove having a straight portion facing in parallel, and the drive lever is in surface contact with the inner peripheral surface of the long groove with the straight portion. A focal plane shutter, characterized in that the linking part is integrally bent. 2. The focal plane according to claim 1, wherein the linking portion formed on the drive lever is bent and bent on the drive lever so that a cross-sectional shape in a plane including the long groove is rectangular. Shutter.