JPH019940Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to a focal plane shutter for a camera.

(Prior Art) A focal plane shutter is known in which two sets of shutter blades divided into a plurality of parts are supported on the sides of an exposure opening and are caused to travel sequentially to control exposure. Since this type of shutter blade is formed from a thin metal plate, it generally has a large inertia and operating torque during operation, and also has the drawbacks of large noise and impact when it stops operating.

For this reason, as seen in Japanese Utility Model Application No. 54-81731, there are shutters in which each blade is made of a synthetic resin material to reduce the inertia during operation. In order to provide the required strength to the mechanism, it is necessary to provide another bridge member between the arms, or to form the slit-forming blades from metal, which increases the number of parts and makes it difficult to reduce inertia etc. I have a problem where I can't do it.

(Purpose) The present invention was created in view of these problems, and its purpose is to reduce the inertia etc. during operation as much as possible while giving the parallel link mechanism the necessary strength. An object of the present invention is to provide an improved focal plane shutter capable of

(Structure) That is, the present invention consists of two groups of blades each consisting of a plurality of blades that run in succession to each other for exposure operation, and two groups of blades constituting a parallelogram each pivotally supported on the side of the shutter opening. In a focal plane shutter for a camera supported on an arm,
Among the plurality of blades constituting the blade group, a blade formed of a thin metal plate is connected to the side closest to the shaft support of the two arms to form a side that maintains parallelism of the arms, and the other blades are connected to the side closest to the shaft support of the two arms. A focal plane shutter for a camera is characterized in that it is formed of a synthetic resin thin plate and supported on the free end sides of the two arms.

Therefore, the details of the present invention will be explained below based on illustrated embodiments.

FIG. 1 shows an embodiment of the present invention, and reference numeral 1 in the figure indicates a substrate in which an opening 1a for film exposure is formed. The opening blade group 3 for opening the opening 1a during the exposure operation consists of an opening slit forming blade 3a and shielding blades 3b, 3c, and the opening slit forming blade 3a and the subsequent shielding blade 3b are made of a light-shielding synthetic resin thin plate. Rotatably supported shafts 4e and 5 are formed on the substrate 1.
The two open arms 4 and 5 are connected to each other with pins 4a, 5a, 4b, and 5b in the middle, and are configured so that they can run in parallel. The shielding blade 3c on the side closer to 5e is formed of a thin metal plate so as to constitute a strong parallel link mechanism together with the two arms 4 and 5.

On the other hand, the closing blade group 6 for closing the opening 1a at the end of exposure consists of four blades, a closing slit forming blade 6a and shielding blades 6b, 6c, and 6d. Forming blade 6a followed by two shielding blades 6 that move a lot
b, 6c are formed of light-shielding synthetic resin thin plates, and pins 7a to c, 8a to two closing arms 7 and 8 are rotatably supported on the substrate 1 by shafts 7e and 8e.
The shielding blade 6d on the side closer to the pivot supports 5e, 7e with the least movement is formed of a thin metal plate, and is connected with a pin to ensure parallel movement of the closing arms 7, 8. They are connected by 7d and 8d.

Next, the operation of the shutter configured in this way will be explained. When the shutter is released by a known method in conjunction with the depression of the camera's release button, the metal shielding blade 3c, which does not move much,
One of the two open arms 4, which is coupled to ensure accurate parallel movement, is released and begins to turn to the right due to the force of a spring (not shown), creating a link mechanism that utilizes the properties of a parallelogram. Accordingly, the light open slit forming blade 3a made of synthetic resin and the shielding blade 3b following it are lightly run downward in parallel together with the metal shielding blade 3c to open the opening 1a. After the release of the open blade group 3, when the desired exposure time has elapsed and the closing arm 7 is unlocked by a known device, the metal shielding blade 6d with little movement is released.
The closing arms 7 and 8, which swing while maintaining an accurate parallelogram while being connected to the slit, respectively direct downward the light closing slit forming blades 6a and the shielding blades 6b and 6c, which have large movements due to the force of a spring (not shown). The opening 1a is closed by running parallel to the opening 1a, and the exposure operation is completed.

When charging the shutter, the opening arm 4 and the closing arm 7 are rotated to the left against a spring force (not shown) using a known method and locked in the state shown in the figure.

As is clear from the above explanation, according to the present invention,
The blades with a small amount of momentum are made of thin metal plates, and the other blades with a lot of momentum are made of thin sheets of synthetic resin, so the mechanical strength of the link mechanism is ensured without the need for special members, and the operation is improved. The inertia and operating torque can be significantly reduced.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a focal plane shutter that is an embodiment of the present invention. 3a, 3b...Synthetic resin blades, 6a, 6
b, 6c...Synthetic resin blades, 3c, 6d...
Metal wings, 4, 5...open arms, 7, 8...
...Closing arm, 4e, 5e, 7e... Pivotal support.

Claims (1)

[Scope of utility model registration request] A camera focus in which two sets of blades, each consisting of a plurality of blades that run in succession for exposure operation, are supported by two arms forming a parallelogram that are each pivoted on the side of the shutter opening. In the Calplane shutter, a blade formed of a thin metal plate among the plurality of blades constituting the blade group is connected to the side closest to the shaft support of the two arms to form a side that maintains the parallelism of the arms. With,
A focal plane shutter for a camera, characterized in that the other blade is formed of a synthetic resin thin plate and supported on the free end sides of the two arms.