JPH0640937U - Focal plane shutter - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] To stop the shutter blades instantaneously and reliably with a simple structure and to improve the durability of the engaging portion between the drive lever and the blade arm. A drive lever 10 axially attached to a shutter base plate 7 by a drive shaft 14 is provided with a spring 15 as a driving force source.
Similarly, via the blade arm 3 axially attached to the shutter base plate 7, a plurality of blade groups are moved to move between a developed state and a superposed state. Here, as for the engagement relationship between the blade arm 3 and the drive lever 10, the drive lever 10 and the long groove 3e formed in the blade arm 3 and having linear portions facing each other in parallel.
Surface contact is achieved by the linking portion 10a having a rectangular cross section formed by being bent.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 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 driving member that drives the blade with the blade.

[0002]

[Prior art]

 In a focal plane shutter, in order to obtain an extremely high shutter speed, in principle, the traveling speed of the blade during exposure is increased and the slit width (exposure forming blade of the leading blade during exposure) is increased. It is achieved by narrowing the distance between the rear blade and the exposed blade of the rear blade as much as possible. This slit width control is performed by electrically controlling the timing of the trailing blade start after the leading blade start. However, the narrower the slit width, the more difficult the accurate reproducibility becomes. Therefore, accurate shutter speed cannot be expected. In particular, when a high shutter speed of 1/4000 seconds or more is realized by narrowing the slit width, this effect cannot be ignored and becomes a serious problem. Therefore, it is important to increase the traveling speed of the blade to make the slit width as wide as possible when pursuing even higher shutter speeds, and this will result in stable shutter speeds with accurate repeatability. The exposure accuracy is improved. It is also advantageous to increase the traveling speed of the blades from the viewpoint of increasing the strobe synchronization speed so that the strobe can be used when the shutter speed is higher on the higher shutter side.

[0003]

[Problems to be solved by the device]

 In such a shutter, when the blade moves from the running state to the stop, the blade tries to continue traveling due to inertia, while the drive member tries to stop due to the braking force applied to the stop. The force to do so acts. In high-speed travel type shutters, the urging force on the blades is increased to increase the traveling speed, and this is stopped.Therefore, a larger load is applied to the engaging portion between the drive member and the blades. . The portion to which the load is concentrated is the portion where the drive lever and the blade arm are in contact with each other. Conventionally, the linkage portion provided in the drive lever and engaging with the groove of the blade arm is Since cylindrical and axial shapes were used and the contact was point contact, deformation and destruction were likely to occur. Further, conventionally, since the cylindrical or shaft-shaped linking portion is fixed by caulking or the like, steps corresponding to that are required.

The present invention has been made in view of the above problems, and an object of the present invention is to make it extremely easy to manufacture without complicating or increasing the size, and in addition to the conventional method. It is an object of the present invention to provide a long-life focal-plane shutter that can be used for an ultra-high-speed shutter without deformation or destruction of the blade arm or the linking part due to the concentration of force due to point contact.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the focal plane shutter of the present invention comprises a shutter base plate having an opening, a blade group including a plurality of divided blades, and a shutter base plate swingably mounted on the shutter base plate. A blade arm connected to the blade group and a shutter base plate pivotally mounted on the shutter base plate coaxially with the blade arm so as to expand the blade group at the opening through the blade arm. And a driving lever for traveling between the overlapping state and the overlapping state, the blade arm is formed with a long groove having a straight portion facing in parallel, and the drive lever is provided with an inner peripheral surface of the long groove. The linking portion that is in surface contact with the straight portion is integrally formed.

[0006]

[Action]

 With the above structure, 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, and the impact force of the collision at the time of stop is large. Will be distributed in the range of Sa. In other words, the impact force per unit area at one stop is much smaller than that of the conventional point contact configuration, which means that durability is dramatically improved. Connect Further, by forming the structure as claimed in claim 2, its manufacture becomes extremely easy.

[0007]

【Example】

 Hereinafter, the present invention will be described in detail with reference to illustrated embodiments. FIG. 1 shows an initial state of 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 and blade arms 5 and 6 for running the respective blade groups. FIG. 4 is a plan view showing that the opening 7a formed in the shutter base plate 7 is blocked 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. The leading blade group 1 is composed of divided blades 1a, 1b, 1c, 1d, rotatably caulked to the blade arm 3 by the shafts 3a, 3b, 3c, 3d, and by the shafts 4a, 4b, 4c, 4d. It is crimped to 4 freely. A link portion 10a formed on a drive lever 10 described later penetrates a slot 7b formed on the shutter base plate 7 and engages with a long groove 3e of the blade arm 3. When the linking portion 10a is caused to travel along the slot 7b, the blade arm 3 rotates right about the rotation shaft 8, and the blade arm 4 interlocked with this also rotates right around the rotation shaft 9, so that the divided blade The front blade group 1 constituted by 1a, 1b, 1c and 1d travels downward and opens the opening 7a.

The blade arms 5 and 6 are swingably 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, and is rotatably caulked to the blade arm 5 by shafts 5a, 5b, 5c, 5d, and the shaft 6a is not shown. , 6b, 6c, 6d are swaged to the blade arm 6 by rotation. A link 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 is caused to travel along the slot 7c, the blade arm 5 rotates right about the rotary shaft 11, and the blade arm 6 interlocked therewith also rotates right around the rotary shaft 12, so that the divided blades 2a, The rear blade group 2 constituted by 2b, 2c and 2d runs downward and shields the opening 7a.

FIG. 2 is a plan view showing an initial state of a drive lever 10 for moving the front blade group 1 and a drive lever 13 for moving the rear blade group 2 of the focal plane shutter according to the embodiment of the present invention. It is a figure. FIG. 3 is a perspective view of the driving lever 10 of the focal plane shutter according to the embodiment of the present invention.

The drive lever 10 for traveling the front blade group 1 is swingably attached to the shutter base plate 7 by a drive shaft 14 coaxial with the rotary shaft 8, and is biased in a clockwise direction by a spring 15. However, since the iron piece 16 disposed on the drive lever 10 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 link portion 10a formed on the drive lever 10 also maintains the initial state, that is, the deployed state. Similarly, the drive lever 13 for moving the rear blade group 2 is swingably attached to the shutter base plate 7 by a drive shaft 17 coaxial with the rotary shaft 11, and is rotated clockwise by a spring 18. Although being biased, the iron piece 19 disposed on the drive lever 13 is attracted by an electromagnet (not shown), so that the initial state is maintained. Therefore, the trailing blade group 2 connected to the blade arm 5 engaged with the linking portion 13a formed on the drive lever 13 also maintains the initial state, that is, the overlapping state.

After that, at the time of exposure, the electromagnet of the iron piece 16 is first released, and the drive lever 10 is rotated by the biasing force of the spring 15, and after a preset time, the electromagnet of the iron piece 19 is released and driven. The lever 13 is rotated by the bias of the spring 18. Then, at the predetermined position, the stop braking action is applied to the drive lever by various methods.

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

[0014]

[Effect of device]

 As described above, in the focal plane shutter according to the present invention, since the surface contact is equivalent to the thickness of the blade arm member, the impact force of the collision at the time of stop is within the range of this contact area. Will be distributed. In other words, the impact force per unit area at the time of one stop is significantly smaller than in the case of the conventional point contact or line contact configuration.

Therefore, the local wear damage does not proceed as in the conventional case, and the average wear is extremely gentle over a wide area, so that the initial state of the member is maintained for a long period of time, and the running characteristics of the shutter blades are also improved. The initial state can be secured for a long time. In addition, since the average wear is extremely gentle over a wide area, it is not possible for the wearer to suddenly become unusable as a result of local progress of wear as in the past, and the user can perceive it as a gradual change over time. It can be done, and the sense of use will be more reliable.

Further, since the linking portion is bent from the drive lever surface and is integrally formed of a metal material, the strength is remarkably improved as compared with the conventional caulking pin, the number of parts can be reduced, and the manufacturing can be performed. Is also very easy.

[Brief description of drawings]

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

FIG. 3 is a perspective view of a drive lever that drives a leading blade of a focal plane shutter according to an embodiment of the present invention.

[Explanation of symbols]

 1 Front blade 2 Rear blade 3, 4, 5, 6 Blade arm 7 Shutter base plate 8, 9, 11, 12 Rotation shaft 10a, 13a Linkage part 10,13 Drive lever 14,17 Drive shaft 15,18 Spring 16,19 Iron piece

Claims (2)

[Scope of utility model registration request] 1. 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 that is pivotally mounted on the shutter base plate coaxially with the blade arm so that the blade group can travel between the expanded state and the superposed state at the opening through the blade arm. The blade arm is formed with a long groove having a shape of a straight line portion facing each other in parallel, and the drive lever is integrally formed with a linking portion that makes surface contact with the inner peripheral surface of the long groove at the straight line portion. A focal-plane shutter featuring. 2. The focal plane shutter according to claim 1, wherein the linking portion formed on the drive lever is formed by bending the drive lever and has a rectangular cross-sectional shape.